[cisco-voip] RTP and Bluecoat

[Mladen Milanovic]

I have customer that is running a Riverbed between all IPT sites. We
officially recommend that all Riverbed devices have to stay out of the
path for voice traffic. I had couple of conference calls with riverbed
support and learn that Riverbed will be transparent for UDP traffic, but
it will try to optimize TCP (signaling) traffic. 

 

Customer configure Riverbed to be "transparent" for signaling but on
some sites we have latency in the call establishment. Other sites works
fine. This is reported as a intermittent problem, but I am blaming
misconfiguration on the Riverbed side. Recently we had a major outage
because of faulty NIC in the riverbed.

 

>From the QoS perspective because we didn't know what riverbed is doing,
we place Access lists for traffic selection on the MPLS edge routers and
deploy LLQ on the serial interface. Using this method we keep consistent
QoS configuration for the voice, and leave data to be handled by
riverbed.

 

Long story short, if I can avoid anything on the voice path and rely to
the Cisco I would prefer this. After this project, I would recommend to
all may customers to avoid this as much as possible. This is very
difficult to troubleshoot.

 

 

Mladen

 

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Wes Sisk
Sent: Wednesday, April 09, 2008 3:01 PM
To: Tim Reimers
Cc: Cisco VoIP List
Subject: Re: [cisco-voip] RTP and Bluecoat

 

Hi Tim,

That is *NOT* an official Cisco recommendation.  I participate here as a
user sharing my experiences just like everyone else.  Official
recommendations come from account teams on printed letterhead.

/Wes

Tim Reimers wrote: 

That certainly sounds like an official "Cisco says not to do that" sort
of answer  ;-)

 

Meaning you can now go back to your IT managers and say "we can't do
that to calls, and you have to purchase/find a way NOT to send calls
through that device"

 

;-)

 

I did that with WAN management hw at my previous employer-- they wanted
to do that as well, and once I could get a Cisco rep to say "not a good
idea" - that was all that was needed to kill off that particular bit of
IT management crazy-thinking....they immediately didn't want to do
anything Cisco recommended against.

 

 

 

________________________________

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Wes Sisk
Sent: Wednesday, April 09, 2008 2:36 PM
To: Nick Griffin
Cc: Cisco VoIP List
Subject: Re: [cisco-voip] RTP and Bluecoat

We've run into a bit of fun with WAN Optimizers, not vendor specific
though:
1. extra delay/latency.  must consider the added delay and latency for
signaling and media thresholds especially related to user experience
2. preservation (or not) of DSCP bits.  we've encountered several WCCP
engines that discard the DSCP bits and thus loose all QoS.

Generally not a good idea for media or signaling traffic for setting up
media.  Of course it can be made to work with careful planning and
observation depending on your resources and motivations.

/Wes

Nick Griffin wrote: 

Does anyone have any experience good/bad or indifferent regarding
running voice rtp traffic through a blue coat wan optimizer? I
personally don't care for the idea, but it seems the situation has came
up and I'm wondering if you folks have any best practices, gotchas etc,
those of you who have done it in the past.

Thanks in advance

Nick Griffin





________________________________



 
_______________________________________________
cisco-voip mailing list
cisco-voip at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-voip
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://puck.nether.net/pipermail/cisco-voip/attachments/20080409/f9dfc2f1/attachment.html