Судьба пакета. Cisco IOS XE


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Диагностику многих проблем на маршрутизаторе Cisco с операционной системой IOS XE можно начать с Packet Trace. Это трассировка обработки пакета внутри маршрутизатора, появившаяся не так давно. Ранее такой функционала был доступен только на межсетевых экранах ASA. Кто использовал packet-tracer на ASA, согласится — очень удобный инструмент. Теперь его аналог появился и на современных маршрутизаторах (ISR 4000, ASR, CRS).

Заметку я построю на живых примерах. Так проще получить представление о IOS-XE Packet Trace. Детали всегда можно найти на сайте вендора. Жаль, что там пока не много информации на этот счёт. По ходу нашего погружения вы поймёте, о чём я.

В качестве подопытного имеем маршрутизатор ISR 4000 (про специфику работы ISR 4000 и IOS XE я уже писал на Хабре). На нём настроен ряд технологий: статическая маршрутизация, PfR, PBR, трансляция адресов (NAT), межсетевой экран ZFW, ACL на интерфейсах, Flexible NetFlow, NBAR2, IPSec, GRE, VTI и прочее. Всё это сделает трассировку более насыщенной и приближённой к реальной эксплуатации.

Есть множество технологий и у каждой свой метод отладки. Чтобы не тратить время и сразу определить, где искать причину проблемы, как раз и пригодится Packet Trace.

Наблюдать будем за ICMP пакетом (echo request), отправленным с адреса 192.168.20.8 на 8.8.8.8.

Активация трассировки состоит из двух частей. Для начала запускаем условный отладчик (conditional debug). Именно в нём мы указываем, какие пакеты нас интересуют. В нашем случае это трафик, описываемый ACL 199 и поступающий на маршрутизатор через интерфейс GigabitEthernet0/0/0:

access-list 199 permit icmp host 192.168.20.8 host 8.8.8.8
debug platform condition interf GigabitEthernet0/0/0 ipv4 access-list 199 ingress
debug platform condition start

Условный отладчик используется не только для работы packet trace. Этот инструмент позволяет эффективно фильтровать лог-сообщения и сообщения отладчика (debug) на этапе их генерации. Мы можем задать условия и видеть записи, касающиеся только того, что нам нужно.
Далее включаем непосредственно packet trace. Указываем буфер и глубину трассировки. Минимально — 16 пакетов. Глубина: базовая (path-trace) или расширенная (fia-trace). В случае расширенной мы получим детальный вывод работы всех функций внутри процесса QFP. Именно он отвечает за передачу пакетов (datapath).
debug platform packet-trace packet 16 fia-trace
debug platform packet-trace enable

По сравнению с ASA packet-tracer синтаксис, конечно, не такой удобный.
ASA packet-tracer может сам генерировать пакеты для дальнейшей трассировки. IOS-XE Packet Trace этого делать не умеет. Для его работы, необходимо, чтобы пакет откуда-нибудь пришёл.
Команды для чистки хвостов. Пригодятся, когда со всем закончим.
no debug platform packet-trace enable
clear platform packet-trace statistics
clear platform condition all

Всё настроено. Запускаем пинг, чтобы нужный нам пакет прошёл через маршрутизатор.
Смотрим общий вывод по пакетам, попавшим в packet trace.
cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/1.5         FWD 

Он у нас один. Пришёл через интерфейс Gi0/0/0 и был передан дальше (состояние FWD) через Gi0/0/1.5.
Смотрим трассировку его обработки
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 8
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/1.5
  State     : FWD 
  Timestamp
    Start   : 6495209991683323 ns (02/18/2017 11:59:43.176192 UTC)
    Stop    : 6495209991814307 ns (02/18/2017 11:59:43.176323 UTC)
Path Trace
  Feature: IPV4                                             <=================
    Input       : GigabitEthernet0/0/0                      <=================
    Output      : GigabitEthernet0/0/0                      <=================
    Source      : 192.168.20.8                              <=================
    Destination : 8.8.8.8                                   <=================
    Protocol    : 1 (ICMP)                                  <=================
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 4960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 5280 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 1600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL
    Lapsed time : 40160 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e88 - IPV4_INPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e68 - IPV4_INPUT_FOR_US_MARTIAN
    Lapsed time : 1440 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 236
    cft_bucket_number     : 566799
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8                  <=================
    tuple.dst_ip          : 8.8.8.8                       <=================
    tuple.src_port        : 61609                         <=================
    tuple.dst_port        : 161                           <=================
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP                          <=================
    tuple.l3_protocol     : IPV4                          <=================
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 236
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d83558 - IPV4_INPUT_STILE_LEGACY
    Lapsed time : 226240 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7b508 - IPV4_INGRESS_MMA_LOOKUP
    Lapsed time : 66880 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d59618 - IPV4_INPUT_FME_PROCESS
    Lapsed time : 2560 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000084
    input vrf_idx         : 0
    calling feature       : FNF
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 236
    cft_bucket_number     : 566799
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 61609
    tuple.dst_port        : 161
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 236
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6dc84 - IPV4_INPUT_FNF_AOR_FIRST
    Lapsed time : 21120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6d9d4 - IPV4_INPUT_FNF_FIRST
    Lapsed time : 119520 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e8c - IPV4_INPUT_VFR
    Lapsed time : 1280 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b660 - IPV4_INPUT_CENT_SMP_PROCESS
    Lapsed time : 3840 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000080
    input vrf_idx         : 0
    calling feature       : CENT
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 236
    cft_bucket_number     : 566799
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 61609
    tuple.dst_port        : 161
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 236
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b62c - IPV4_INPUT_CENT_RC_PROCESS
    Lapsed time : 40640 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7ff70 - IPV4_INPUT_PBR              <=================
    Lapsed time : 34720 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d858d0 - IPV4_INPUT_TCP_ADJUST_MSS   <=================     
    Lapsed time : 2560 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0                     <=================
    Output      : GigabitEthernet0/0/1.5                   <=================
    Entry       : 0x8113ac40 - IPV4_INPUT_LOOKUP_PROCESS   <=================
    Lapsed time : 4160 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc88 - IPV4_INPUT_FNF_AOR_FINAL
    Lapsed time : 1280 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6d974 - IPV4_INPUT_FNF_FINAL
    Lapsed time : 218880 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc8c - IPV4_INPUT_FNF_AOR_RELEASE
    Lapsed time : 2560 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e94 - IPV4_INPUT_IPOPTIONS_PROCESS
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac44 - IPV4_INPUT_GOTO_OUTPUT_FEATURE
    Lapsed time : 4480 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e98 - IPV4_OUTPUT_VFR
    Lapsed time : 1920 ns
  Feature: ZBFW                                            <=================
    Action  : Fwd                                          <=================
    Zone-pair name  : in-out1                              <=================
    Class-map name  : CM-FW_in-out                         <=================
    Input interface : GigabitEthernet0/0/0                 <=================
    Egress interface: GigabitEthernet0/0/1.5               <=================
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d70b28 - IPV4_OUTPUT_INSPECT
    Lapsed time : 721760 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d77188 - MC_OUTPUT_GEN_RECYCLE
    Lapsed time : 3680 ns
  Feature: NAT                                             <=================
    Direction   : IN to OUT                                <=================
    Action      : Translate Source                         <=================
    Old Address : 192.168.20.8  00001                      <=================
    New Address : 87.87.87.87 00033                        <=================
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d7c390 - IPV4_NAT_OUTPUT_FIA
    Lapsed time : 54880 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d85d30 - IPV4_OUTPUT_THREAT_DEFENSE
    Lapsed time : 1600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e9c - IPV4_VFR_REFRAG
    Lapsed time : 960 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Output
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 238
    cft_bucket_number     : 566799
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 87.87.87.87
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 61609
    tuple.dst_port        : 161
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 238
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d8359c - IPV4_OUTPUT_STILE_CLR_TXT
    Lapsed time : 137600 ns
  Feature: IPSec                                            <=================
    Result    : IPSEC_RESULT_DENY                           <=================
    Action    : SEND_CLEAR                                  <=================
    SA Handle : 0    
    Peer Addr : 8.8.8.8                                     <=================
    Local Addr: 87.87.87.87                                 <=================
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d761ac - IPV4_OUTPUT_IPSEC_CLASSIFY
    Lapsed time : 50560 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e70 - IPV4_OUTPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 7040 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81128eb0 - IPV4_OUTPUT_L2_REWRITE
    Lapsed time : 7040 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e74 - IPV4_OUTPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131ec4 - IPV4_OUTPUT_FRAG
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81133e50 - IPV4_OUTPUT_DROP_POLICY
    Lapsed time : 13600 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6d914 - IPV4_OUTPUT_FNF_FINAL
    Lapsed time : 112800 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113bb40 - MARMOT_SPA_D_TRANSMIT_PKT
    Lapsed time : 41440 ns

Объём трассировки напрямую зависит от настроенных функций. Если бы у нас была только маршрутизация, данных было бы существенно меньше.

Часть названий понятна. Но присутствуют этапы, декодировать которые достаточно непросто. Документация вендора пока в этом плане не сильно помогает.

Выделим наиболее интересные моменты

1. Информация, идентифицирующая наш поток (flow) данных:

Feature: CFT
    …
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 61609
    tuple.dst_port        : 161
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4

Данные хранят в таблице CFT (Common Flow Table). Их используют технологии, которые оперируют в своей работе информацией о каждом потоке (Netflow, NBAR, PfR и пр.). Таблица CFT необходима, чтобы не хранить избыточную информацию.

2. Определение исходящего интерфейса:
Когда пакет только попал на маршрутизатор, исходящий интерфейс не определён. Подставляется входящий:


Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 8.8.8.8
    Protocol    : 1 (ICMP)

После того как определено, куда дальше слать пакет (выполнена функция маршрутизации), исходящий интерфейс меняется:
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac40 - IPV4_INPUT_LOOKUP_PROCESS
    Lapsed time : 4160 ns

3. Данные об обработке пакета межсетевым экраном ZFW:
  Feature: ZBFW
    Action  : Fwd
    Zone-pair name  : in-out1
    Class-map name  : CM-FW_in-out
    Input interface : GigabitEthernet0/0/0
    Egress interface: GigabitEthernet0/0/1.5

Мы сразу видим, между какими зонами проходил пакет, и в какой класс он попал. Это достаточно удобно, так как конфигурация ZFW зачастую очень запутана.

4. Информация о трансляции адресов:

  Feature: NAT
    Direction   : IN to OUT
    Action      : Translate Source
    Old Address : 192.168.20.8  00001
    New Address : 87.87.87.87 00033

Адрес назначения в пакете был заменён на 87.87.87.87.

5. Так как на нашем маршрутизаторе настроен IPSec, будет отмечено, попал ли в него пакет:

  Feature: IPSec
    Result    : IPSEC_RESULT_DENY
    Action    : SEND_CLEAR
    SA Handle : 0
    Peer Addr : 8.8.8.8
    Local Addr: 87.87.87.87

Нет, не попал.

В трейсах представлено достаточно много дополнительной информации. Например, IPV4_INPUT_PBR сигнализирует о том, что пакет прошёл через PBR. Но информации, был ли применен PBR или пакет передан на обработку стандартным правилам маршрутизации, в этом разделе мы не найдём. В нашем случае пакет не попал под правила PBR. Запись IPV4_INPUT_TCP_ADJUST_MSS говорит о том, что на интерфейсе настроена команда ip tcp adjust-mss. При этом, как и в предыдущем примере, никаких деталей мы не получаем.

Большая часть информации, выводимой устройством, не представляет интереса. Однако ситуация будет меняться, когда с пакетом что-то пойдёт не так.

Ситуация №1. Пакет отброшен ACL на входном интерфейсе

cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/0           DROP   8   (Ipv4Acl)

Пакет был отброшен (DROP), так как сработал ACL (Ipv4Acl).
Трассировка обработки пакета
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 35
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/0
  State     : DROP 8   (Ipv4Acl)
  Timestamp
    Start   : 6515970748260480 ns (02/18/2017 17:45:43.568889 UTC)
    Stop    : 6515970748313558 ns (02/18/2017 17:45:43.568942 UTC)
Path Trace
  Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 8.8.8.8
    Protocol    : 1 (ICMP)
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 6560 ns
  Feature: FIA_TRACE                               
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 5920 ns                              
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 1440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d8375c - STILE_LEGACY_DROP_EXT
    Lapsed time : 3680 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7b554 - INGRESS_MMA_LOOKUP_DROP_EXT
    Lapsed time : 63040 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6e0f8 - INPUT_DROP_FNF_AOR_EXT
    Lapsed time : 8320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6dc44 - INPUT_FNF_DROP_EXT
    Lapsed time : 324800 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6e6c8 - INPUT_DROP_FNF_AOR_RELEASE_EXT
    Lapsed time : 8320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81128ebc - INPUT_DROP_EXT                 <=================
    Lapsed time : 1920 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL                 <=================
    Lapsed time : 794240 ns

INPUT_DROP_EXT и IPV4_INPUT_ACL сообщают, что пакет был отброшен именно на входящем интерфейсе. Трейсы получились короткими, как жизнь пакета.

Ситуация №2. Пакет отброшен ACL на исходящем интерфейсе

cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/1.5         DROP   8   (Ipv4Acl)

И снова пакет не был передан (DROP) из-за ACL (Ipv4Acl). Теперь, правда, в качестве исходящего интерфейса фигурирует Gi0/0/1.5.
Трассировка обработки пакета
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 33
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/0
  State     : DROP 8   (Ipv4Acl)
  Timestamp
    Start   : 6515547984424423 ns (02/18/2017 17:38:40.479689 UTC)
    Stop    : 6515547984571057 ns (02/18/2017 17:38:40.479835 UTC)
Path Trace
  Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 8.8.8.8
    Protocol    : 1 (ICMP)
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 8320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 4320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 3520 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL
    Lapsed time : 43360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e88 - IPV4_INPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e68 - IPV4_INPUT_FOR_US_MARTIAN
    Lapsed time : 1280 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 5
    cft_bucket_number     : 1591662
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 443
    tuple.dst_port        : 57521
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 5
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d83558 - IPV4_INPUT_STILE_LEGACY
    Lapsed time : 222240 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7b508 - IPV4_INGRESS_MMA_LOOKUP
    Lapsed time : 67200 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d59618 - IPV4_INPUT_FME_PROCESS
    Lapsed time : 2240 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000084
    input vrf_idx         : 0
    calling feature       : FNF
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 5
    cft_bucket_number     : 1591662
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 443
    tuple.dst_port        : 57521
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 5
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6dc84 - IPV4_INPUT_FNF_AOR_FIRST
    Lapsed time : 22080 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6d9d4 - IPV4_INPUT_FNF_FIRST
    Lapsed time : 136320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e8c - IPV4_INPUT_VFR
    Lapsed time : 1280 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b660 - IPV4_INPUT_CENT_SMP_PROCESS
    Lapsed time : 2560 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000080
    input vrf_idx         : 0
    calling feature       : CENT
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 5
    cft_bucket_number     : 1591662
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 443
    tuple.dst_port        : 57521
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 5
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b62c - IPV4_INPUT_CENT_RC_PROCESS
    Lapsed time : 40160 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7ff70 - IPV4_INPUT_PBR
    Lapsed time : 39520 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d858d0 - IPV4_INPUT_TCP_ADJUST_MSS
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac40 - IPV4_INPUT_LOOKUP_PROCESS
    Lapsed time : 4320 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc88 - IPV4_INPUT_FNF_AOR_FINAL
    Lapsed time : 1920 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6d974 - IPV4_INPUT_FNF_FINAL
    Lapsed time : 274240 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc8c - IPV4_INPUT_FNF_AOR_RELEASE
    Lapsed time : 2400 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e94 - IPV4_INPUT_IPOPTIONS_PROCESS
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac44 - IPV4_INPUT_GOTO_OUTPUT_FEATURE
    Lapsed time : 2880 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e98 - IPV4_OUTPUT_VFR
    Lapsed time : 1600 ns
  Feature: ZBFW
    Action  : Fwd
    Zone-pair name  : in-out1
    Class-map name  : CM-FW_in-out
    Input interface : GigabitEthernet0/0/0
    Egress interface: GigabitEthernet0/0/1.5
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d70b28 - IPV4_OUTPUT_INSPECT
    Lapsed time : 989760 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d77188 - MC_OUTPUT_GEN_RECYCLE
    Lapsed time : 2720 ns
  Feature: NAT
    Direction   : IN to OUT
    Action      : Translate Source
    Old Address : 192.168.20.8  00001
    New Address : 87.87.87.87 00036
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d7c390 - IPV4_NAT_OUTPUT_FIA
    Lapsed time : 36800 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d85d30 - IPV4_OUTPUT_THREAT_DEFENSE
    Lapsed time : 3200 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e9c - IPV4_VFR_REFRAG
    Lapsed time : 1120 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Output
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 7
    cft_bucket_number     : 1591662
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 87.87.87.87
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 443
    tuple.dst_port        : 57521
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 7
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d8359c - IPV4_OUTPUT_STILE_CLR_TXT
    Lapsed time : 141920 ns
  Feature: IPSec
    Result    : IPSEC_RESULT_DENY
    Action    : SEND_CLEAR
    SA Handle : 0
    Peer Addr : 8.8.8.8
    Local Addr: 87.87.87.87
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d761ac - IPV4_OUTPUT_IPSEC_CLASSIFY
    Lapsed time : 46080 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e70 - IPV4_OUTPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 2560 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81128eb8 - OUTPUT_DROP_EXT                  <=================
    Lapsed time : 3360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d4a144 - IPV4_OUTPUT_ACL                  <=================
    Lapsed time : 121760 ns

В трейсах в самом конце мы обнаружим информацию о судьбе пакета: OUTPUT_DROP_EXT и IPV4_OUTPUT_ACL. Пакет практически вырвался из лап маршрутизатора, о чём свидетельствует прохождение большинства стадий обработки.

Ситуация №3. Пакет отброшен межсетевым экраном

cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/1.5         DROP   184 (FirewallPolicy)

Пакет отброшен (DROP). Причина — политики межсетевого экрана (FirewallPolicy).
Трассировка обработки пакета
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 36
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/1.5
  State     : DROP 184 (FirewallPolicy)
  Timestamp
    Start   : 6516783739710881 ns (02/18/2017 17:59:16.560339 UTC)
    Stop    : 6516783739809427 ns (02/18/2017 17:59:16.560438 UTC)
Path Trace
  Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 8.8.8.8
    Protocol    : 1 (ICMP)
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 8800 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 5440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 1600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL
    Lapsed time : 47360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e88 - IPV4_INPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e68 - IPV4_INPUT_FOR_US_MARTIAN
    Lapsed time : 1440 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 135
    cft_bucket_number     : 875224
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 56789
    tuple.dst_port        : 514
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 135
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d83558 - IPV4_INPUT_STILE_LEGACY
    Lapsed time : 202560 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7b508 - IPV4_INGRESS_MMA_LOOKUP
    Lapsed time : 63360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d59618 - IPV4_INPUT_FME_PROCESS
    Lapsed time : 4640 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000084
    input vrf_idx         : 0
    calling feature       : FNF
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 135
    cft_bucket_number     : 875224
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 56789
    tuple.dst_port        : 514
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 135
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6dc84 - IPV4_INPUT_FNF_AOR_FIRST
    Lapsed time : 20640 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6d9d4 - IPV4_INPUT_FNF_FIRST
    Lapsed time : 127360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e8c - IPV4_INPUT_VFR
    Lapsed time : 1440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b660 - IPV4_INPUT_CENT_SMP_PROCESS
    Lapsed time : 2720 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000080
    input vrf_idx         : 0
    calling feature       : CENT
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 135
    cft_bucket_number     : 875224
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 56789
    tuple.dst_port        : 514
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 135
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b62c - IPV4_INPUT_CENT_RC_PROCESS
    Lapsed time : 43840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7ff70 - IPV4_INPUT_PBR
    Lapsed time : 37120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d858d0 - IPV4_INPUT_TCP_ADJUST_MSS
    Lapsed time : 1280 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac40 - IPV4_INPUT_LOOKUP_PROCESS
    Lapsed time : 4800 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc88 - IPV4_INPUT_FNF_AOR_FINAL
    Lapsed time : 1760 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6d974 - IPV4_INPUT_FNF_FINAL
    Lapsed time : 255680 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d6dc8c - IPV4_INPUT_FNF_AOR_RELEASE
    Lapsed time : 2240 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e94 - IPV4_INPUT_IPOPTIONS_PROCESS
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x8113ac44 - IPV4_INPUT_GOTO_OUTPUT_FEATURE
    Lapsed time : 4160 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81131e98 - IPV4_OUTPUT_VFR
    Lapsed time : 1760 ns
  Feature: ZBFW                                           <=================
    Action  : Drop                                        <=================
    Reason  : ICMP policy drop:classify result            <=================                 
    Zone-pair name  : in-out1                             <=================
    Class-map name  : class-default                       <=================
    Input interface : GigabitEthernet0/0/0                <=================
    Egress interface: GigabitEthernet0/0/1.5              <=================
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x81128eb8 - OUTPUT_DROP_EXT            <=================
    Lapsed time : 640 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.5
    Entry       : 0x80d70b28 - IPV4_OUTPUT_INSPECT        <=================
    Lapsed time : 639200 ns

Наличие сообщений OUTPUT_DROP_EXT и IPV4_OUTPUT_INSPECT показывает, что пакет отброшен политиками инспектирования, которое выполняется как раз МСЭ. Детали находим в информации по ZFW:
Feature: ZBFW
    Action  : Drop
    Reason  : ICMP policy drop:classify result
    Zone-pair name  : in-out1
    Class-map name  : class-default
    Input interface : GigabitEthernet0/0/0
    Egress interface: GigabitEthernet0/0/1.5

Reason сообщает о том, что пакет был классифицирован, как ICMP. Класс, в который попал пакет и где он был отброшен, — class-default.

Ситуация №4. Пакет маршрутизируется правилами PBR

cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/1.6         FWD

Пакет передан (FWD). Теперь исходящий интерфейс Gi0/0/1.6.
Трассировка обработки пакета
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 36
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/1.6
  State     : FWD 
  Timestamp
    Start   : 6517659109765260 ns (02/18/2017 18:13:51.930393 UTC)
    Stop    : 6517659109927732 ns (02/18/2017 18:13:51.930556 UTC)
Path Trace
  Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 8.8.8.8
    Protocol    : 1 (ICMP)
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 10400 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 5440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 1600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL
    Lapsed time : 265600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e88 - IPV4_INPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e68 - IPV4_INPUT_FOR_US_MARTIAN
    Lapsed time : 3680 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 69
    cft_bucket_number     : 2000178
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 57521
    tuple.dst_port        : 443
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 69
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d83558 - IPV4_INPUT_STILE_LEGACY
    Lapsed time : 223360 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7b508 - IPV4_INGRESS_MMA_LOOKUP
    Lapsed time : 85440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d59618 - IPV4_INPUT_FME_PROCESS
    Lapsed time : 3040 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000084
    input vrf_idx         : 0
    calling feature       : FNF
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 69
    cft_bucket_number     : 2000178
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 57521
    tuple.dst_port        : 443
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 69
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6dc84 - IPV4_INPUT_FNF_AOR_FIRST
    Lapsed time : 19680 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d6d9d4 - IPV4_INPUT_FNF_FIRST
    Lapsed time : 153600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e8c - IPV4_INPUT_VFR
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b660 - IPV4_INPUT_CENT_SMP_PROCESS
    Lapsed time : 2560 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x00000080
    input vrf_idx         : 0
    calling feature       : CENT
    direction             : Input
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 69
    cft_bucket_number     : 2000178
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 192.168.20.8
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 57521
    tuple.dst_port        : 443
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 69
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4b62c - IPV4_INPUT_CENT_RC_PROCESS
    Lapsed time : 49600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d7ff70 - IPV4_INPUT_PBR              <=================
    Lapsed time : 69760 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d858d0 - IPV4_INPUT_TCP_ADJUST_MSS
    Lapsed time : 1440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0                     <=================
    Output      : GigabitEthernet0/0/1.6                   <=================
    Entry       : 0x8113ac40 - IPV4_INPUT_LOOKUP_PROCESS
    Lapsed time : 7840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d6dc88 - IPV4_INPUT_FNF_AOR_FINAL
    Lapsed time : 1600 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d6d974 - IPV4_INPUT_FNF_FINAL
    Lapsed time : 280480 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d6dc8c - IPV4_INPUT_FNF_AOR_RELEASE
    Lapsed time : 3840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131e94 - IPV4_INPUT_IPOPTIONS_PROCESS
    Lapsed time : 960 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x8113ac44 - IPV4_INPUT_GOTO_OUTPUT_FEATURE
    Lapsed time : 3840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131e98 - IPV4_OUTPUT_VFR
    Lapsed time : 5440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d858a0 - IPV4_OUTPUT_TCP_ADJUST_MSS
    Lapsed time : 1280 ns
  Feature: ZBFW
    Action  : Fwd
    Zone-pair name  : in-out2
    Class-map name  : CM-FW_in-out
    Input interface : GigabitEthernet0/0/0
    Egress interface: GigabitEthernet0/0/1.6
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d70b28 - IPV4_OUTPUT_INSPECT
    Lapsed time : 789120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d77188 - MC_OUTPUT_GEN_RECYCLE
    Lapsed time : 11200 ns
  Feature: NAT
    Direction   : IN to OUT
    Action      : Translate Source
    Old Address : 192.168.20.8
    New Address : 62.62.62.62
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d7c390 - IPV4_NAT_OUTPUT_FIA
    Lapsed time : 38400 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d85d30 - IPV4_OUTPUT_THREAT_DEFENSE
    Lapsed time : 4000 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131e9c - IPV4_VFR_REFRAG
    Lapsed time : 800 ns
  Feature: CFT
    API                   : cft_handle_pkt
    packet capabilities   : 0x0000008c
    input vrf_idx         : 0
    calling feature       : STILE
    direction             : Output
    triplet.vrf_idx       : 0
    triplet.network_start : 0x01003f8e
    triplet.triplet_flags : 0x00000000
    triplet.counter       : 71
    cft_bucket_number     : 2000178
    cft_l3_payload_size   : 40
    cft_pkt_ind_flags     : 0x00000000
    cft_pkt_ind_valid     : 0x00000931
    tuple.src_ip          : 62.62.62.62
    tuple.dst_ip          : 8.8.8.8
    tuple.src_port        : 57521
    tuple.dst_port        : 443
    tuple.vrfid           : 0
    tuple.l4_protocol     : ICMP
    tuple.l3_protocol     : IPV4
    pkt_sb_state          : 0
    pkt_sb.num_flows      : 0
    pkt_sb.tuple_epoch    : 71
    returned cft_error    : 14
    returned fid          : 0x00000000
  Feature: NBAR
    Packet number in flow: N/A
    Classification state: Final
    Classification name: ping
    Classification ID: [CANA-L7:479]
    Number of matched sub-classifications: 0
    Number of extracted fields: 0
    Is PA (split) packet: False
    TPH-MQC bitmask value: 0x0
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d8359c - IPV4_OUTPUT_STILE_CLR_TXT
    Lapsed time : 140160 ns
  Feature: IPSec
    Result    : IPSEC_RESULT_DENY
    Action    : SEND_CLEAR
    SA Handle : 0
    Peer Addr : 8.8.8.8
    Local Addr: 62.62.62.62
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d761ac - IPV4_OUTPUT_IPSEC_CLASSIFY
    Lapsed time : 66400 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131e70 - IPV4_OUTPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 3840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81128eb0 - IPV4_OUTPUT_L2_REWRITE
    Lapsed time : 13440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131e74 - IPV4_OUTPUT_SRC_LOOKUP_CONSUME
    Lapsed time : 1120 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81131ec4 - IPV4_OUTPUT_FRAG
    Lapsed time : 2240 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x81133e50 - IPV4_OUTPUT_DROP_POLICY
    Lapsed time : 18720 ns
  Feature: OCE_TRACE
    Type       : OCE_ADJ_IPV4
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x80d6d914 - IPV4_OUTPUT_FNF_FINAL
    Lapsed time : 113440 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/1.6
    Entry       : 0x8113bb40 - MARMOT_SPA_D_TRANSMIT_PKT
    Lapsed time : 43680 ns

Если мы сравним трассировку пакета при маршрутизации стандартными правилами (статическая маршрутизация) и при маршрутизации правилами PBR, мы не увидим разницы. Изменятся только исходящий интерфейс, и адрес, подставляемый в NAT«е.

Ситуация №5. Пакет передаётся через VTI интерфейс

В этом примере пингуем адрес 172.28.0.1.

cbs-4000#show platform packet-trace summary
Pkt   Input             Output            State  Reason
0     Gi0/0/0           Gi0/0/1.5         FWD

Пакет передан (FWD). Исходящий интерфейс Gi0/0/1.5.
Трассировка обработки пакета
cbs-4000#show platform packet-trace packet 0
Packet: 0           CBUG ID: 50
Summary
  Input     : GigabitEthernet0/0/0
  Output    : GigabitEthernet0/0/1.5
  State     : FWD 
  Timestamp
    Start   : 6665377802839987 ns (02/20/2017 11:15:48.257340 UTC)
    Stop    : 6665377803172303 ns (02/20/2017 11:15:48.257673 UTC)
Path Trace
  Feature: IPV4
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Source      : 192.168.20.8
    Destination : 172.28.0.1
    Protocol    : 1 (ICMP)
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x8112bfbc - DEBUG_COND_INPUT_PKT
    Lapsed time : 5600 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e84 - IPV4_INPUT_SRC_LOOKUP_ISSUE
    Lapsed time : 4160 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e64 - IPV4_INPUT_DST_LOOKUP_CONSUME
    Lapsed time : 3040 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x80d4a140 - IPV4_INPUT_ACL
    Lapsed time : 19840 ns
  Feature: FIA_TRACE
    Input       : GigabitEthernet0/0/0
    Output      : GigabitEthernet0/0/0
    Entry       : 0x81131e8
    
            

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