Test Round Trip Delay Between VCS Cluster Nodes

Introduction

This document describes how to test Round Trip Delay (RTT) between Cisco Video Communication Servers (VCSs). Each peer in a cluster must be within a 15ms hop (30ms RTT) of each and every other VCS to be added into the cluster.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on Cisco VCS.

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.

Related Products

This document can also be used with these hardware and software versions:

• Cisco TelePresence Conductor
• Cisco Expressway Core
• Cisco Expressway Edge

Test RTT

Complete these steps to test RTT.

1. Log into a cluster member VCS as root and ping the other cluster member with this command:
   
   

   ping -i 0.03 -s 4000 10.83.23.28

   
   
   
2. Let the ping run for one to two minutes:
   
   

   4008 bytes from 10.83.23.28: icmp_req=1 ttl=64 time=0.266 ms
   4008 bytes from 10.83.23.28: icmp_req=2 ttl=64 time=0.213 ms
   4008 bytes from 10.83.23.28: icmp_req=3 ttl=64 time=0.214 ms
   4008 bytes from 10.83.23.28: icmp_req=4 ttl=64 time=0.213 ms
   4008 bytes from 10.83.23.28: icmp_req=5 ttl=64 time=0.213 ms
   4008 bytes from 10.83.23.28: icmp_req=6 ttl=64 time=0.218 ms
   4008 bytes from 10.83.23.28: icmp_req=7 ttl=64 time=0.219 ms
   4008 bytes from 10.83.23.28: icmp_req=8 ttl=64 time=0.219 ms
   4008 bytes from 10.83.23.28: icmp_req=9 ttl=64 time=0.219 ms
   4008 bytes from 10.83.23.28: icmp_req=10 ttl=64 time=0.221 ms
   4008 bytes from 10.83.23.28: icmp_req=11 ttl=64 time=0.225 ms
   4008 bytes from 10.83.23.28: icmp_req=12 ttl=64 time=0.225 ms
   4008 bytes from 10.83.23.28: icmp_req=13 ttl=64 time=0.230 ms
   4008 bytes from 10.83.23.28: icmp_req=14 ttl=64 time=0.227 ms
   4008 bytes from 10.83.23.28: icmp_req=15 ttl=64 time=0.229 ms
   4008 bytes from 10.83.23.28: icmp_req=16 ttl=64 time=0.232 ms
   4008 bytes from 10.83.23.28: icmp_req=17 ttl=64 time=0.231 ms
   4008 bytes from 10.83.23.28: icmp_req=18 ttl=64 time=0.230 ms
   4008 bytes from 10.83.23.28: icmp_req=19 ttl=64 time=0.232 ms
   4008 bytes from 10.83.23.28: icmp_req=20 ttl=64 time=0.230 ms
   4008 bytes from 10.83.23.28: icmp_req=21 ttl=64 time=0.234 ms
   4008 bytes from 10.83.23.28: icmp_req=22 ttl=64 time=0.233 ms
   4008 bytes from 10.83.23.28: icmp_req=23 ttl=64 time=0.235 ms
   4008 bytes from 10.83.23.28: icmp_req=24 ttl=64 time=0.236 ms
   4008 bytes from 10.83.23.28: icmp_req=25 ttl=64 time=0.234 ms
   4008 bytes from 10.83.23.28: icmp_req=26 ttl=64 time=0.236 ms
   4008 bytes from 10.83.23.28: icmp_req=27 ttl=64 time=0.237 ms
   4008 bytes from 10.83.23.28: icmp_req=28 ttl=64 time=0.235 ms
   4008 bytes from 10.83.23.28: icmp_req=29 ttl=64 time=0.235 ms
   4008 bytes from 10.83.23.28: icmp_req=30 ttl=64 time=0.218 ms
   4008 bytes from 10.83.23.28: icmp_req=31 ttl=64 time=0.220 ms
   4008 bytes from 10.83.23.28: icmp_req=32 ttl=64 time=0.226 ms
   4008 bytes from 10.83.23.28: icmp_req=33 ttl=64 time=0.254 ms
   4008 bytes from 10.83.23.28: icmp_req=34 ttl=64 time=0.214 ms
   4008 bytes from 10.83.23.28: icmp_req=35 ttl=64 time=0.214 ms
   4008 bytes from 10.83.23.28: icmp_req=36 ttl=64 time=0.215 ms
   4008 bytes from 10.83.23.28: icmp_req=37 ttl=64 time=0.214 ms

   
   
   
3. Press Ctrl + C in order to stop the ping after one to two minutes. A summary with the average RTT displays at the end of the output:
   
   

   --- 10.83.23.28 ping statistics ---
   159 packets transmitted, 159 received, 0% packet loss, time 4739ms
   rtt min/avg/max/mdev = 0.195/0.236/0.283/0.022 ms