Callmanager multicast traffic

[Pogle]

Hi,

I wonder of somebody can help. I have inherited a VOIP infrastructure which I am slowly learning to administer. I have the following questions:
1) When I run a network analyse it shows that over 97% of the traffic is UDP multicasts from the 2 callmanager servers to the following addresses: 239.1.1.1, 239.2.2.2, 239.2.2.14 & 239.2.2.6. Any ideas what this is and is it normal?
2) Can you recommend a good book for shedding light on "best practises" and how to administer the Callmanager/VOIP infrastructure?

Regards,

Phil

 

[simonxts]

The UDP multicast is the music-on-hold stream going across the LAN.