Categories: CCIE , Cisco , Cisco VOIP -  Comments
Spent the past several days going over Lab 7: Media and Lab 8:High Availability. Although both Labs were pretty straight forward and most of the tasks I have configured several times, I was still able to learn a few new things.
Lab 7: Media
Since I was working in my lab, I had to skip the first couple of tasks that included configuring ports on the Catalyst 6500 (6508 blade) for a conference bridge and transcoder. These tasks are relatively easy and I have practiced them several times during rented rack time, so not a big deal skipping. I did practice configuring IOS Conference Bridge and transcoder using the “new” way with profiles as well as the “old” way on the NM-HDV card. I believe the exam blueprint has the NM-HDV listed so it is recommended that you know both ways of configuration. With the “old way”, there is no need to define profiles. The configuration should look something like below:
Dspfarm services dspfarm
Dspfarm transcoder maximum sessions 2
Dspfarm confbridge maximum sessions 1
Sccp local vlan20
Sccp ccm 10.10.1.11 priority 1
Sccp ccm 10.10.1.10 priority 2
One task not listed, but I still wanted to configure was to multicast MOH from the router’s flash. Before doing this, I did go ahead and configure my MOH servers for Multicast, enabled multicast routing on routers, and made sure all the necessary interfaces were configured for PIM. The Initial task requested that HQ receive multicast MOH using G711 codec and BR1 receive MOH using G729 codec. No issues here as I was able to accomplish what was asked. Next I decided configure BR1 router to multicast MOH from flash. I added the needed configurations into Call-Manager-Fallback.
I ran into two issues:
1. I had configured the MOH servers to Multicast using the default address of 126.96.36.199 and increment on IP address. Since BR1 was receiving MOH in G729, the multicast address was 188.8.131.52 and I had configured 184.108.40.206. After some reading, I learned that Incrementation is triggered by a change in codec as well as the number of audio sources. Hence, source 1 g711mu-law would be 220.127.116.11; source 1 g711a-law would be 18.104.22.168 and so on. Once I configured the correct IP address in my Multicast statement, I ran into issue number 2.
2. The audio file I was using in CCM was different than the file I had in BR1 routers flash. When I would place a call on hold, I would now hear BOTH of the audio files at the same time. What was happening was that CCM was multicasting as well as the router on the same address. Turning off multicast routing on the BR1 router resolved issue and now I was only hearing the audio file multicasting from flash.
A couple of useful commands:
show ccm-manager music-on-hold – Use this command to verify that MOH is multicast.
debug ephone moh – used to verify that the SRST gateway is multicasting.
** TIP **
Unless it specifically states something different, to keep things simple, it is best to create a Region and Device Pool for G711 and assign it to your MOH servers. This way you will know to just put 22.214.171.124 on routers where you are multicasting from flash.
Lab 8: High Availability
This lab focused mostly on configuring AAR and also SRST on the BR1 router. No issues with getting AAR to work. Dropped the locations bandwidth to 23 for BR1 and 4 digit dialing from BR1 to HQ was re-routed out the PSTN successfully. For SRST, configured the basic settings as well as had to preserve 4 digit dialing to HQ and BR2, and also maintain Class of Restriction. I was instructed not to use “prefix” or translations rules to maintain 4 digit dialing. I used Num expansion to go from 4 digit to full E164 and created dial peers for each to send calls out the PSTN successfully. To maintain Class of Restriction, I used IOS COR and applied to outbound dialpeers as well as the proper DNs within Call-Manager-Fallback.
Tomorrow I have my first 8 hour Proctor Labs rack time scheduled. I plan on connecting with the EzVPN solution so hopefully I won’t have any issues. Part of the time will be spent getting familiar with how everything works on PL racks. The remaining time I plan on working on IPexpert Workbook Vol 2 Multiprotocol Challenge A.