[cisco-voip] Cisco 871 - Voice over DMVPN

[Carlos Ortiz]

Matt,

 

I'd also be interested in ideas from others regarding this setup.  We
are currently using ASA 5505's for our remote IP phone users but have
not run into bandwidth issues yet with only 7 of them.   Do you do any
policing or Traffic Shaping outbound on your 871W remote routers?  That
might offer some short term relief from remote users with large Internet
pipes.  

 

Your first idea (2 DMVPN tunnels) - seems plausible but also seems like
more work and maintenance.

 

The second idea (ASA proxy) seems like a solution that is picking up
steam.  I also like the fact that it will simplify the remote setup
since you don't require a router or ASA.

 

Here is a link to an article I recently saw on ASA proxy.

 

http://www.networkworld.com/community/node/42488

 

 

Carlos

 

 

 

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Matthew
Linsemier
Sent: Wednesday, July 29, 2009 11:18 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] Cisco 871 - Voice over DMVPN

 

Hey all,

I'm throwing this out again to see if anyone can offer some assistance.
If I should post in the DMVPN forum, I can do so as well, but I figured
I would start here.

I am in the process of refreshing my Cisco 871 router configurations
(5th build now ) and I was looking for some input in regards to
maintaining my voice quality the best I can over the Internet.  I have
been doing voice over IPSec for the last 5-6 years and it seems like it
never gets easier. :)

Right now we have about 35 users deployed remotely using Cisco 871W
routers and Cisco 7960 phones behind them.  They are connected to two
DMVPN hubs (for redundancy).  We have voice prioritized (among other
items) within the Tunnels and all works as expected (utilizing priority
queues, qos pre-classify, etc.).   

With the increase in home user bandwidth (10 meg / 12 meg) we are
starting to notice congestion on our 6 meg Internet link when large
amounts of data is sent or received over the tunnel Interfaces, which in
the end causes congestion, which in turn effects call quality.  We
utilize PacketShaper's on the internet links to prioritize IPSec
traffic, but when all the traffic is IPSec traffic, there are issues.  

I am looking into some possibilities of removing the voice traffic to
maintain call quality at all costs, and I have come up with a few ideas.

1.	Creating two DMVPN tunnels, one that carries only voice, and the
other that carries the rest of the data, and then using the PacketShaper
to guarantee bandwidth to the DMVPN tunnel that carries voice above all
other data. 
2.	Pulling the voice traffic out of the tunnel and using PhoneProxy
on the ASA's then utilizing PacketShaper to guarantee bandwidth to the
srtp session above all other data.


If anyone can throw out some pros and cons to either of these ideas, I
would like to hear them.  Also, if anyone knows of a better appliance
for managing QoS at the Internet level other than the PacketShaper, I
would like to hear that as well (outside of Cisco IOS QoS).

Thanks in advance,

Matt 

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