Configure Layer 3 CTS with Ingress Reflector
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Contents
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.
Troubleshoot
There is currently no specific troubleshooting information available for this configuration.
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