Introduction
This document describes Security Group Tag Exchange Protocol (SXP) Propagation method configuration in Software-Defined Wide-Area Networks (SD-WAN).
Prerequisites
Requirements
Cisco recommends that you have knowledge of these topics:
- Cisco Catalyst Software-Defined Wide Area Network (SD-WAN)
- Software-Defined Access (SD-Access) Fabric
- Cisco Identify Service Engine (ISE)
Components Used
The information in this document is based on:
- Cisco IOS® XE Catalyst SD-WAN Edges version 17.9.5a
- Cisco Catalyst SD-WAN Manager version 20.12.4.
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, ensure that you understand the potential impact of any command.
Background Information
Cisco TrustSec Integration
SGT Propagation with Cisco TrustSec Integration is supported by Cisco IOS® XE Catalyst SD-WAN Release 17.3.1a and onwards. This feature enables Cisco IOS® XE Catalyst SD-WAN edge devices to propagate Security Group Tag (SGT) inline tags that are generated by Cisco TrustSec-enabled switches in the branches to other edge devices in the Cisco Catalyst SD-WAN network.
Basic concepts of Cisco TrustSec:
- SGT Bindings: Association between IP and SGT, all bindings have the most common configuration and learn directly from the Cisco ISE.
- SGT Propagation: The propagation methods are used to propagate these SGTs between network hops.
- SGTACLs Policies: Set of rules that specify the privileges of a traffic source within a trusted network.
- SGT Enforcement: Where the policies are enforced, based on the SGT Policy.
SGT Propagation Methods
The SGT propagation methods are:
- SGT Propagation Inline Tagging
- SGT SXP Propagation
SGT Propagation with SXP
For Inline Tagging Propagation, the branches need to be equipped with Cisco TrustSec-enabled switches that are capable of handling SGT Inline Tagging (Cisco TrustSec Devices). If the hardware does not support Inline Tagging, SGT Propagation uses Security Group Tag Exchange Protocol (SXP) to propagate SGTs across network devices.
Cisco ISE allows creating an IP-to-SGT Binding (Dynamic IP-SGT) and then downloads IP-SGT Binding using SXP to a Cisco IOS® XE Catalyst SD-WAN device for propagation of the SGT over the Cisco Catalyst SD-WAN network. Also, the policies for the SGT traffic on SD-WAN egress are enforced by downloading SGACL Policies from ISE.
Example:
- The Cisco Switch (Border node) does not support Inline Tagging (non-TrustSec device).
- Cisco ISE allows downloading IP-SGT Binding through SXP connection to a Cisco IOS® XE Catalyst SD-WAN device (Edge Router).
- Cisco ISE allows downloading SGACL Policies through the Radius integration and PAC key to a Cisco IOS® XE Catalyst SD-WAN device (Edge Router).
Requirements to Enable the SXP Propagation and Download SGACL Policies on SD-WAN Edge Devices
Note: SGACL Policies are not enforced on the ingress traffic, only on egress traffic in a Cisco Catalyst SD-WAN network.
Note: Cisco TrustSec feature is not supported for more than 24K SGT Policies in controller mode.
Enable SGT SXP Propagation and Download SGACL Policies
Network Diagram for SGT SXP Propagation in SD-WAN
Step 1. Configure the Radius Parameters
- Log in to Cisco Catalyst SD-WAN Manager GUI.
- Navigate to Configuration > Templates > Feature Template > Cisco AAA. Click RADIUS SERVER.
- Configure RADIUS SERVER parameters and Key.
RADIUS Server Configuration
- Enter the values to configure Radius Group parameters.
RADIUS Group Configuration
- Enter the values to configure Radius COA parameters.
RADIUS COA Configuration
Note: If Radius COA is not configured, SD-WAN router is not able to download the SGACL Policies automatically. After create o modify a SGACL Policy from ISE, the command cts refresh policy is used to download the policies.
- Navigate to TRUSTSEC section and enter the values.
TRUSTSEC Configuration
- Attach the Cisco AAA feature template to Device template.
Step 2. Configure the SXP Parameters
- Navigate to Configuration > Templates > Feature Template > TrustSec.
- Configure the CTS credentials and assign a SGT Binding to device Interfaces.
TrustSec Feature Template
- Navigate to SXP Default section and enter the values to configure the SXP Default parameters.
SXP Default Configuration
- Navigate to SXP Conection and configure the SXP Connection parameters, then click Save.
SXP Connection Configuration
Note: Cisco ISE has a limit on the number of SXP sessions it can handle. Therefore, as an alternative, a SXP Reflector for scale network horizontal could be used.
Note: It is recommended to use an SXP reflector to establish an SXP peer with Cisco IOS® XE Catalyst SD-WAN devices.
- Navigate to Configuration > Templates > Device Template > Additional Templates > TrustSec.
- Select the TrustSec feature template previously created, click Save.
Additional Templates Section
Verify
Run the command show cts sxp connections vrf (service vrf)
to display the Cisco TrustSec SXP connections information.
#show cts sxp connections vrf 4001
SXP : Enabled
Highest Version Supported: 5
Default Password : Set
Default Key-Chain: Not Set
Default Key-Chain Name: Not Applicable
Default Source IP: 192.168.35.2
Connection retry open period: 120 secs
Reconcile period: 120 secs
Retry open timer is not running
Peer-Sequence traverse limit for export: Not Set
Peer-Sequence traverse limit for import: Not Set
----------------------------------------------
Peer IP : 10.88.244.146
Source IP : 192.168.35.2
Conn status : On
Conn version : 4
Conn capability : IPv4-IPv6-Subnet
Conn hold time : 120 seconds
Local mode : SXP Listener
Connection inst# : 1
TCP conn fd : 1
TCP conn password: default SXP password
Hold timer is running
Total num of SXP Connections = 1
Run the command show cts role-based sgt-map
to display the global Cisco TrustSec SGT map between IP-Address and SGT Bindings.
#show cts role-based sgt-map vrf 4001 all
Active IPv4-SGT Bindings Information
IP Address SGT Source
============================================
192.168.1.2 2 INTERNAL
192.168.35.2 2 INTERNAL
192.168.39.254 8 SXP <<< Bindings learned trough SXP for the host connected in the LAN side
IP-SGT Active Bindings Summary
============================================
Total number of CLI bindings = 0
Total number of SXP bindings = 1
Total number of INTERNAL bindings = 2
Total number of active bindings = 3
Run the command show cts environment-data
to display the global Cisco TrustSec Environment Data.
#show cts environment-data
CTS Environment Data
====================
Current state = COMPLETE
Last status = Successful
Service Info Table:
Local Device SGT:
SGT tag = 2-01:TrustSec_Devices
Server List Info:
Installed list: CTSServerList1-0002, 1 server(s):
Server: 10.88.244.146, port 1812, A-ID B546BF54CA5778A0734C8925EECE2215
Status = ALIVE
auto-test = FALSE, keywrap-enable = FALSE, idle-time = 60 mins, deadtime = 20 secs
Security Group Name Table:
0-00:Unknown
2-01:TrustSec_Devices
3-00:Network_Services
4-00:Employees
5-00:Contractors
6-00:Guests
7-00:Production_Users
8-02:Developers <<<<< Security Group assigned to the host connected in the LAN side (SGT 8)
9-00:Auditors
10-00:Point_of_Sale_Systems
11-00:Production_Servers
12-00:Development_Servers
13-00:Test_Servers
14-00:PCI_Servers
15-01:BYOD
Environment Data Lifetime = 86400 secs
Run the command show cts pacs
to display the Cisco TrustSec PAC provisioned.
#show cts pacs
AID: B546BF54CA5778A0734C8925EECE2215
PAC-Info:
PAC-type = Cisco Trustsec
AID: B546BF54CA5778A0734C8925EECE2215
I-ID: FLM2206W092
A-ID-Info: Identity Services Engine
Credential Lifetime: 22:24:54 UTC Tue Dec 17 2024
PAC-Opaque: 000200B80003000100040010B546BF54CA5778A0734C8925EECE22150006009C00030100BE30CE655A7649A5CED883C180441AEB0000001366E8735300093A8094E1BBCE5D372901E5A6288648367A3D022FD850D2EFD91A9479B97560B0386BB5C202F0484D9B24CFD1DAB3074323F4F723A12667438BAFB600262D384E203AB48EF7BB2A44588C44740A1FF8AD56F83D28B75F6C8741F40639BFB9E651F99D8E6268465F19415DF21BE6853550850C87DEA0676AD124DD9DCC14BD
Run the command show cts role-based permissions
to display the SGACL Policies.
#show cts role-based permissions
IPv4 Role-based permissions default:
Permit IP-00
IPv4 Role-based permissions from group 5:Contractors to group 2:TrustSec_Devices:
Deny IP-00
IPv4 Role-based permissions from group 5:Contractors to group 8:Developers:
DNATELNET-00
IPv4 Role-based permissions from group 5:Contractors to group 15:BYOD:
Deny IP-00
Run the command show cts rbacl (SGACLName)
to display the access control list (SGACL) configuration.
#show cts rbacl DNATELNET
CTS RBACL Policy
================
RBACL IP Version Supported: IPv4 & IPv6
name = DNATELNET-00
IP protocol version = IPV4, IPV6
refcnt = 2
flag = 0xC1000000
stale = FALSE
RBACL ACEs:
deny tcp dst eq 23 log <<<<< SGACL action
permit ip
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