Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Configure

Network Diagram

Step 1. Setup CTS Layer3 on Egress Interface between SW1 and SW2

Step 2. Enable CTS Ingress Reflector Globally

Verify

Troubleshoot

Introduction

This document describes how to configure the Layer 3 Cisco TrustSec (CTS) with Ingress Reflector.

Prerequisites

Requirements

Cisco recommends that you have basic knowledge of CTS solution.

Components Used

The information in this document is based on these software and hardware versions:

- Catalyst 6500 Switches with Supervisor Engine 2T on IOS® Release 15.0(01)SY

- IXIA Traffic Generator

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.

Background Information

CTS is an advanced network access control and identity solution to provide end-to-end secure connectivity across Service Providers backbone and Data Center networks.

The Catalyst 6500 switches with Supervisor Engine 2T and 6900 Series line cards provide complete hardware and software support in order to implement CTS. When a Catalyst 6500 is configured with the Supervisor Engine 2T and 6900 Series line cards, the system is fully capable of providing CTS features.

Since customers would like to continue to use their Catalyst 6500 switches and line cards that already exist while they migrate to a CTS network, and for this reason, Supervisor Engine 2T needs to be compatible with certain line cards that already exist when deployed in a CTS network.

In order to support new CTS functionality such as Security Group Tag (SGT) and IEEE 802.1AE MACsec link encryption, there are dedicated application-specific integrated circuits (ASICs) used on the Supervisor Engine 2T and the new 6900 Series line cards. Ingress reflector mode provides compatibility between legacy line cards that do not use CTS. Ingress reflector mode supports only centralized forwarding, packet forwarding will occur on the PFC of Supervisor Engine 2T. Only 6148 Series or fabric-enabled Centralized Forwarding Card (CFC) line cards such as the 6748-GE-TX line cards are supported. The Distributed Forwarding Card (DFC) Line cards and 10 Gigabit Ethernet line cards are not supported when ingress reflector mode is enabled. With ingress reflector mode configured, non-supported line cards do not power up. Ingress reflector mode is enabled with the use of a global configuration command and requires a system reload.

Configure

Network Diagram

Step 1. Setup CTS Layer3 on Egress Interface between SW1 and SW2

- SW1(config)#int t1/4/2

SW1(config-if)#ip address 172.16.0.1 255.255.255.0

SW1(config-if)# cts layer3 ipv4 trustsec forwarding

SW1(config-if)# cts layer3 ipv4 policy

SW1(config-if)#no shutdown

SW1(config-if)#exit

SW2(config)#int t1/2

SW2(config-if)#ip address 172.16.0.2 255.255.255.0

SW2(config-if)# cts layer3 ipv4 trustsec forwarding

SW2(config-if)# cts layer3 ipv4 policy

SW2(config-if)#no shutdown

SW2(config-if)#exit

Step 2. Enable CTS Ingress Reflector Globally

SW1(config)#platform cts ingress

SW1#sh platform  cts

CTS Ingress mode enabled

Connect an interface from a NON CTS supported line card to IXIA.

SW1#sh run int gi2/4/1

Building configuration...

Current configuration : 90 bytes

!

interface GigabitEthernet2/4/1

no switchport

ip address 10.10.10.1 255.255.255.0

end

Assign static SGT in SW1 switch for packets received from the IXIA 1 connected to SW1. Setup permit policy to do CTS L3 only for packets in the desired subnet on authenticator.

SW1(config)#cts role-based sgt-map 10.10.10.10 sgt 15

SW1(config)#ip access-list extended traffic_list

SW1(config-ext-nacl)#permit ip 10.10.10.0 0.0.0.255 any

SW1(config)#cts policy layer3 ipv4 traffic traffic_list

Verify

Use this section in order to confirm that your configuration works properly.

Verify that the IFC-state is OPEN on both switches. The outputs must look like this:

SW1#sh cts int summary

Global Dot1x feature is Enabled

CTS Layer2 Interfaces

---------------------

Interface  Mode    IFC-state dot1x-role peer-id    IFC-cache    Critical Authentication

-----------------------------------------------------------------------------

Te1/4/1    DOT1X   OPEN      Supplic    SW2        invalid  Invalid

Te1/4/4    MANUAL  OPEN      unknown    unknown    invalid  Invalid

Te1/4/5    DOT1X   OPEN      Authent    SW2        invalid  Invalid

Te1/4/6    DOT1X   OPEN      Supplic    SW2        invalid  Invalid

Te2/3/9    DOT1X   OPEN      Supplic    SW2        invalid  Invalid

CTS Layer3 Interfaces

---------------------

Interface   IPv4 encap       IPv6 encap       IPv4 policy      IPv6 policy

Te1/4/2     OPEN             ----------       OPEN             -----------

SW2#sh cts int summary

Global Dot1x feature is Enabled

CTS Layer2 Interfaces

---------------------

Interface  Mode    IFC-state dot1x-role peer-id    IFC-cache    Critical-Authentication

-----------------------------------------------------------------------------

Te1/1      DOT1X   OPEN      Authent    SW1         invalid     Invalid

Te1/4      MANUAL  OPEN      unknown    unknown     invalid     Invalid

Te1/5      DOT1X   OPEN      Supplic    SW1         invalid     Invalid

Te1/6      DOT1X   OPEN      Authent    SW1         invalid     Invalid

Te4/5      DOT1X   OPEN      Authent    SW1         invalid     Invalid

CTS Layer3 Interfaces

---------------------

Interface   IPv4 encap       IPv6 encap       IPv4 policy      IPv6 policy

--------------------------------------------------------------------------

Te1/2       OPEN             ----------       OPEN             -----------

Verify through Netflow Output

Netflow can be configured with these commands:

SW2(config)#flow record rec2

SW2(config-flow-record)#match ipv4 protocol

SW2(config-flow-record)#match ipv4 source address

SW2(config-flow-record)#match ipv4 destination address

SW2(config-flow-record)#match transport source-port

SW2(config-flow-record)#match transport destination-port

SW2(config-flow-record)#match flow direction

SW2(config-flow-record)#match flow cts source group-tag

SW2(config-flow-record)#match flow cts destination group-tag

SW2(config-flow-record)#collect routing forwarding-status

SW2(config-flow-record)#collect counter bytes

SW2(config-flow-record)#collect counter packets

SW2(config-flow-record)#exit

SW2(config)#flow monitor mon2

SW2(config-flow-monitor)#record rec2

SW2(config-flow-monitor)#exit

Apply netflow on the ingress port of SW2 switch interface as shown:

SW2#  sh run int t1/2

Building configuration...

Current configuration : 166 bytes

!

interface TenGigabitEthernet1/2

ip address 172.16.0.2 255.255.255.0

ip flow monitor mon2 input

cts layer3 ipv4 trustsec forwarding

cts layer3 ipv4 policy

end

Send packets from IXIA 1 to IXIA 2. It must be received properly on IXIA 2 connected to the SW2 switch according to the traffic policy. Ensure that the packets are SGT tagged.

SW2#sh flow monitor mon2 cache format  table

Cache type:                               Normal

Cache size:                                 4096

Current entries:                               0

High Watermark:                                0

Flows added:                                   0

Flows aged:                                    0

- Active timeout      (  1800 secs)          0

- Inactive timeout    (    15 secs)          0

- Event aged                                 0

- Watermark aged                             0

- Emergency aged                             0

There are no cache entries to display.

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 4:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 2:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 1:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               4

IPV4 SRC ADDR    IPV4 DST ADDR    TRNS SRC PORT  TRNS DST PORT  FLOW DIRN  FLOW CTS SRC GROUP TAG  FLOW CTS DST GROUP TAG  IPPROT  ip fwd status                  bytes        pkts

===============  ===============  =============  =============  =========  ======================  ======================  =======  ========================================  ==========

1.1.1.10         2.2.2.10                     0              0  Input                          10                       0      255  Unknown                       148121702     3220037

10.10.10.10      10.10.20.10                  0              0  Input                          15                       0      255  Unknown                       23726754      515799

10.10.10.1       224.0.0.5                    0              0  Input                           2                       0       89  Unknown                       9536          119

172.16.0.1       224.0.0.5                    0              0  Input                           0                       0       89  Unknown                       400           5

Now, setup exception policy to skip CTS L3 for packets to a specific IP address in Authenticator switch.

SW1(config)#ip access-list extended exception_list

SW1(config-ext-nacl)#permit ip 10.10.10.0 0.0.0.255 any

SW1(config)#cts policy layer3 ipv4 exception exception_list

SW2#sh flow monitor mon2 cache format table

Cache type:                               Normal

Cache size:                                 4096

Current entries:                               0

High Watermark:                                0

Flows added:                                   0

Flows aged:                                    0

- Active timeout      (  1800 secs)          0

- Inactive timeout    (    15 secs)          0

- Event aged                                 0

- Watermark aged                             0

- Emergency aged                             0

There are no cache entries to display.

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 4:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 2:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               0

There are no cache entries to display.

Module 1:

Cache type:                               Normal (Platform cache)

Cache size:                              Unknown

Current entries:                               3

IPV4 SRC ADDR    IPV4 DST ADDR    TRNS SRC PORT  TRNS DST PORT  FLOW DIRN  FLOW CTS SRC GROUP TAG  FLOW CTS DST GROUP TAG  IP PROT  ip fwd status                  bytes         pkts

===============  ===============  =============  =============  =========  ======================  ======================  =======  ========================================  =========

1.1.1.10         2.2.2.10                     0              0  Input                          10                       0      255  Unknown                        1807478       39293

10.10.10.10      10.10.20.10                  0              0  Input                           0                       0      255  Unknown                        1807478       39293

10.10.10.1       224.0.0.5                    0              0  Input                           2                       0       89  Unknown                        164           2

Send packets from IXIA 1 to IXIA 2. They must be received properly on IXIA 2 connected to the SW2 switch according to the exception policy.

Note: The packets are not SGT tagged because the exception policy takes precedence FLOW CTS SRC GROUP TAG=0.

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.