From: simon hart (simon@harttel.com)
Date: Tue Oct 04 2005 - 17:54:47 GMT-3
Chris,
I guess you could use priority queueing as well, classify your rtp traffic
in an ACL and direct all your voice traffic to the high queue. Not as
efficient as the others method specified as there would be no packet
interleaving and hence you could experience jitter through head of line
blocking.
With respect to point 1. I was unaware that FRF.12 by itself creates two
queues, that is one for packets below the fragment size and those above, my
understanding was that large packets got fragmented just so that smaller
voice packets could get interleaved - all packets then went to one WFQ
queue - do you have any links that explain this in more depth?
With respect to point 2. My understanding here was that with the
introduction of the frame-relay ip rtp priority command you create a high
priority queue within WFQ, and then you voice traffic would get pointed to
that queue.
Simon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of Chris
Lewis
Sent: 04 October 2005 18:18
To: ccielab@groupstudy.com
Subject: Options for prioritizing voice on frame connections
All:
I am aware of the following options for prioritizing voice traffic over a
frame relay DLCI. Does this look complete, or can anyone add to it?
1. Creating a separate high priority queue on the interface
This requires FRF.12 (fragment in the map-class).Data packets larger than
the packet size specified in the frame-relay fragment command are first
enqueued to a WFQ subqueue, whereas the smaller packest go to the high
priority queue. They are then dequeued and fragmented. After fragmentation,
the first segment is transmitted. The remaining segments wait for the next
available transmission time for that VC, as determined by the shaping
algorithm. At this point, small voice packets and fragmented data packets
are interleaved from other PVCs. With this interface level queueing
mechanism, small data packest also get in to the priority queue on the
interface if they are smaller than the fragment size.
2. This can be enhanced by adding frame-relay ip rtp priority. KNown as
VoIPoFR, this classifies VoIP packets by matching on the RTP UDP port range
defined in a Frame Relay map-class. All RTP traffic within this port range
is enqueued to a priority queue for the VC. In addition, voice packets go
into the high priority queue at the interface level. All other packets go
into the non-priority queue at the interface level.
3. The generic form of using MQC to identify voice traffic, then using a
policy-map to give this traffic priority treatment and applying the
service-policy to a class for the DLCI
4. PIPQ configured on the interface using the interface-queue priority
command and assigning a complete DLCI to the priority queue in its
map-class, this of course requires one to dedicate voice to a specific DLCI.
5. Using PPP to fragment and interleave, which is pretty much like F=plain
FRF.12 and assumes that packet size is enough of a differentiator to
separate voice and data packets.
Chris
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