Check 1+1 SP Comms

Apr 2021

Introduction

The 1+1 SPs communicate with each other over the Management network using various ports, these are:

15771 for Mux comms
15772 for Simulcrypt
15778 for stat Mux

We can use tcpdump to monitor the traffic between the Muxes by specifying the relevant port.

tcpdump -i mngt port 15778 -Q out

This will show Stat Mux traffic (as in the stat mux control messages).
The active Mux will show something like below:

tcpdump -i eth0 port 15778 -Q out
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
15:49:22.309719 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:22.851978 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:23.394021 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:23.936007 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:24.478037 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:25.019993 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:25.562039 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:26.104193 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:26.646276 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61
15:49:27.188263 IP sp01.15778 > 235.2.127.254.15778: UDP, length 61