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Cisco Unified Border Element

CUBE-SP Basic Configuration Example

Document ID: 116415

Updated: Aug 13, 2013

Contributed by Kurt Mai, Cisco TAC Engineer.

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Introduction

This document describes a step-by-step configuration for Cisco Unified Border Element-Service Provider (CUBE-SP) on the 1000 Series Aggregation Services Routers (ASR) in order to perform basic call routing.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

  • Basic IP routing
  • VoIP configuration with Integrated Service Router (ISR) CUBE

Components Used

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

  • ASR 1006 with Gigabit Ethernet (Gige) interface card
  • Cisco IOS® XE Version 3.7.2
  • Basic Infrastructure with these IP addresses:
    • SIP UA 1---------SBC----------SIP UA 2
    • SIP UA 1 - 10.201.160.200
    • SIP UA 2 - 10.201.160.201
    • SBC G0/0/0 - 10.201.160.216 (vrf 3945)
    • SBC G0/0/1 - 10.201.160.126 (vrf 3825)

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

Configuration Overview

Here is a summary of the configuration steps covered in this document:

  1. Verify Network Connectivity
  2. VRF Configuration (optional)
  3. Configure ASR to Session Border Controller (SBC) Mode
  4. Configure Adjacencies
  5. Configure Call Routing
  6. Configure Media Address

Verify Network Connectivity

The initial step for this configuration is to verify that you have network connectivity. Network connectivity is required in order to complete the configuration steps described in this document.

VRF Configuration (Optional)

CUBE-SP is multi-VPN Routing and Forwarding (VRF) aware. This means that CUBE-SP receives calls from adjacencies in one VRF, and forwards them to other adjacencies in other VRFs. However, this is not equivalent to IP routing. In order to route between VRF, Border Gateway Protocol (BGP) route leaking is required, but it is not required for call routing among VRF to work. Complete these steps in order to configure the VRF:

  1. Define the VRF:
    !
    vrf definition 3825
     !
     address-family ipv4
    This command is required in order to assign the IP address to VRF enabled interfaces.
     exit-address-family
    !
    vrf definition 3945
     !
     address-family ipv4
     exit-address-family
    !
  2. Assign the VRF to Gigabit Ethernet interfaces:
    !
    interface GigabitEthernet0/0/0
     description Do Not Change
    vrf forwarding 3945
     ip address 10.201.160.216 255.255.255.192
     speed 1000
     no negotiation auto
    !
    interface GigabitEthernet0/0/1
     description Do Not Change
     vrf forwarding 3825
     ip address 10.201.160.126 255.255.255.192
     speed 1000
     no negotiation auto
     cdp enable
    !
  3. Add static routes for each VRF so that the ASR knows how to route:
    ip route vrf 3825 0.0.0.0 0.0.0.0 10.201.160.65
    ip route vrf 3945 0.0.0.0 0.0.0.0 10.201.160.193

Configure Adjacencies

Two SIP adjacencies must be configured: one for the 3945 VRF that points to a 3945 gateway, and the another for the 3825 VRF that points to a 3825 gateway:

sbc SBCNAME

sbe

adjacency sip 3825
    force-signaling-peer
    vrf 3825

This assigns VRF 3825 to this adjacency.

 editor-type editor
    preferred-transport udp
    signaling-address ipv4 10.201.160.126

This is the IP address of the interface in VRF 3825. SIP messages are sent out from this interface, and ASR listens to this interface for SIP messages for this adjacency.

 statistics method summary
    signaling-port 5060

The port ASR will listen for SIP messages.

 remote-address ipv4 10.201.160.200 255.255.255.255 

This is the IP address range of remote SIP gateways/endpoints.

 signaling-peer 10.201.160.200 

SIP messages are sent to this IP address for this adjacency.

 attach 

This "locks/commits" the adjacency configuration.

adjacency sip 3945
    force-signaling-peer
    vrf 3945
    editor-type editor
    preferred-transport udp
    signaling-address ipv4 10.201.160.216
    statistics method summary
    signaling-port 5060
    remote-address ipv4 10.201.160.201 255.255.255.255
    signaling-peer 10.201.160.201
    attach

Configure Call Routing

Call routing in CUBE-SP is policy based. In other words, you write policies for each scenario of incoming calls, and tell the router how to react to each scenario and how to route it.

Here are two simple policies:

  • If a call arrives from the 3825 adjacency, then send the call to the 3945 adjacency.
  • If a call arrives from the 3945 adjacency, then send the call to the 3825 adjacency.
sbc SBCNAME

sbe

call-policy-set 1

This specifies the first call-policy-set. There can be multiple sets at the same time, and you can switch between them quickly. Only one can be active at a time.

 first-call-routing-table table1  

This specifies the entry-point of routing, which is the first table to visit.

 rtg-src-adjacency-table table1 

This is a routing table that makes routing decisions based on which adjacency the call came from (source adjacency).

 entry 1
     match-adjacency 3825
     dst-adjacency 3945

This tells the system to send the calls that arrive from the 3825 adjacency to the 3945 adjacency.

 action complete 

This tells the system to route, or go to the routing table and check again.

entry 2
      match-adjacency 3945
      dst-adjacency 3825
      action complete
    complete

This must be removed before you modify the tables, and issued before the policy set is used.

 call-policy-set default 1 

This specifies the current active routing policy. It must be removed before you modify the policy set.

Configure Media Address

While the adjacency configuration specifies the signaling address and port, the media address and port are not configured per adjacency, but per VRF. For each VRF, a separate media address is needed.

sbc SBCNAME

media-address ipv4 10.201.160.126 vrf 3825
  port-range 16384 32767 any
 media-address ipv4 10.201.160.216 vrf 3945
  port-range 16384 32767 any

Note: For optimum performance, each VRF interface has a secondary IP address along with the primary one. In order to avoid port conflicts, configure the media address with the primary IP, and the signaling address with the secondary IP.

Verify

Use these commands in order to confirm that your configuration works properly:

  • show run  -  Displays the running configuration.
  • show sbc SBCNAME sbe <options> - Displays various information about the SBC.

Troubleshoot

Complete these steps in order to troubleshoot your configuration:

  1. If a call cannot be completed, collect the PD trace from the ASR:
    debug sbc SBCNAME log-level buffer 0 
    This "buffer" is not equivalent to the buffer in "logging buffer." In order to direct the PD trace to "logging buffer," add debug sbc SBCNAME log-level console 0 to the command entry. The number "0" specifies the log level, with "0" being the most verbose.
    sbc dump-diag 
    This clears the trace buffer.
  2. Make a test call:
    sbc dump-diag 
    This creates a new file with the name pdtrc_buf*.* in the default hard drive location.
  3. If there is no audio or one-way audio, verify IP routing:
    ping vrf 3825 10.201.160.200
    ping vrf 3945 10.201.160.20

Related Information

Updated: Aug 13, 2013
Document ID: 116415