Contents

Introduction

Prerequisites

Requirements

Components Used

Configure

Verify

Troubleshoot

Related Information

Introduction

This document describes the procedure to enable packet-trace on IOS-XE platform to capture Policy-Based Routing (PBR) traffic on Cisco's Integrated Service Router (ISR) 4000 series platform.

Contributed by Prathik Krishnappa, Cisco TAC Engineer.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Configure

Here is the configuration to enable packet-trace to debug PBR traffic:

PBR Configurations:

route-map PBR permit 10

match ip address 102

set ip next-hop 192.168.1.18

ip access-list extended 102

permit ip 192.168.1.0 0.0.3.255 any

permit ip 192.168.2.0 0.0.0.255 any

interface GigabitEthernet0/0/1

ip address 192.168.2.10 255.255.255.248

no ip redirects

no ip unreachables

no ip proxy-arp

ip nat inside

ip policy route-map PBR

load-interval 30

negotiation auto

route-map PBR, permit, sequence 10

Match clauses:

ip address (access-lists):102

Set clauses:

ip next-hop 192.168.1.18

Policy routing matches: 500 packets, 400 bytes

- To debug particular subnet, create an access-list:

ip access-list ext 103

permit ip host 192.168.3.10 any

- Apply the access-list in the PBR:

route-map PBR

match ip address 103

- Perform conditional debug on the interface where PBR is applied:

debug platform condition interface gigabitethernet 0/0/1 ipv4 access-list 103 both

- Enable these debugs:

debug platform packet-trace packet 64

debug platform packet-trace packet 16 fia-trace

debug platform packet-trace enable

debug platform condition start

Initiate traffic from the subnet.

Note: Use the Command Lookup Tool (registered customers only) in order to obtain more information on the commands used in this section.

Verify

There is currently no verification procedure available for this configuration.

Troubleshoot

This section provides information you can use in order  to troubleshoot your configuration.

Router #sh debugging

IOSXE Conditional Debug Configs:

Conditional Debug Global State: Start

Conditions Direction

----------------------------------------------------------------------------------------------|---------

GigabitEthernet0/0/1 & IPV4 ACL [102] both

Feature Condition Type Value

-----------------------|-----------------------|--------------------------------

Feature Type Submode Level

------------|-------------|----------------------------------------------------------------------------------------------|----------

IOSXE Packet Tracing Configs:

debug platform packet-trace enable

debug platform packet-trace packet 16 fia-trace data-size 2048

Packet Infra debugs:

Ip Address Port

------------------------------------------------------|----------

show platform packet-trace packet 0 shows the first packet that is traced.

Summary shows that the input packe t is received on gig 0/0/1 and forwarded on to output interface gig 0/0/2 and the state is fwd.

In path trace you can find source and destination ip address.

To verify if the packet is policy based, check: IPV4_INPUT_PBR field.

Feature: FIA_TRACE

Entry      : 0x10f81c00 - IPV4_INPUT_PBR

Lapsed time: 23220 ns

Router#sh platform packet-trace packet 0

Packet: 0           CBUG ID: 458151

Summary

Input     : GigabitEthernet0/0/1

Output    : GigabitEthernet0/0/2

State     : FWD

Timestamp

Start   : 355835562633335 ns (12/28/2016 08:11:52.433136 UTC)

Stop    : 355835562660187 ns (12/28/2016 08:11:52.433163 UTC)

Path Trace

Feature: IPV4

Source      : 192.168.3.10

Destination : 74.125.200.189

Protocol    : 17 (UDP)

SrcPort : 56018

DstPort : 443

Feature: FIA_TRACE

Entry      : 0x10f82018 - DEBUG_COND_INPUT_PKT

Lapsed time: 2060 ns

Feature: FIA_TRACE

Entry      : 0x10f81c38 - IPV4_INPUT_SRC_LOOKUP_ISSUE

Lapsed time: 2160 ns

Feature: FIA_TRACE

Entry      : 0x10f81c34 - IPV4_INPUT_DST_LOOKUP_CONSUME

Lapsed time: 3080 ns

Feature: FIA_TRACE

Entry      : 0x10f81c2c - IPV4_INPUT_SRC_LOOKUP_CONSUME

Lapsed time: 700 ns

Feature: FIA_TRACE

Entry      : 0x10f82000 - IPV4_INPUT_FOR_US_MARTIAN

Lapsed time: 800 ns

Feature: FIA_TRACE

Entry      : 0x10f81c14 - IPV4_INPUT_FNF_FIRST

Lapsed time: 15280 ns

Feature: FIA_TRACE

Entry      : 0x10f81ff4 - IPV4_INPUT_VFR

Lapsed time: 620 ns

Feature: FIA_TRACE

Entry      : 0x10f81c00 - IPV4_INPUT_PBR

Lapsed time: 23220 ns

Feature: FIA_TRACE

Entry      : 0x10f816f4 - IPV4_INPUT_TCP_ADJUST_MSS

Lapsed time: 1500 ns

Feature: FIA_TRACE

Entry      : 0x10f81e90 - IPV4_INPUT_LOOKUP_PROCESS

Lapsed time: 5100 ns

Feature: FIA_TRACE

Related Information

- IOS-XE Datapath Packet Trace Feature

- Technical Support & Documentation - Cisco Systems