From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Tue May 25 2004 - 18:03:39 GMT-3
Vaz,
If you think about it this makes sense to have delayed packets because
your circuit is capable of transmitting much faster than the 1536kbps
shaping. Look at it this way, with a potential 6Mbps clock rate and a
Bc of 192000bps; you are filling up the PVC in 32 milliseconds. (e.g.
192kbps/6000kbps = 32msec)
Now, look at the Tc because you are setting the time interfal (Tc) to
125 msec. So, you are starving the pipe with your traffic shaping
scheme for 93 msec for each spoke site (or 125-32 = 93msec). IOW, your
scheme crams 192kbps in 32msec and is dormant for the remainder of the
shaping time interval (Tc).
I would look into shortening up the time interval by adjusting Bc down.
This should prevent starving out your traffic through the Tc time
intervals.
Obviously don't do this without proper verification of changes to delay
and schedule it during normal maintenance, keep a log and good records
for each iteration, watch for voice traffic starvation... Blah blah blah
blah.. Add infinitum.
Lastly, I would either remove adaptive shaping and the mincir.
Otherwise what are you throttling down to on a BECN especially if you
are contracted for a Full guaranteed 1536kbps why adaptive shape anyhow?
Just shape to the rate and be done.
Also, as good practice, set the traffic shaping on the remote sites too
so that you have matching parameters across hub and spoke sites.
And if I'm wrong I'm sure someone on the list will let me know. 8)
Andy
-----Original Message-----
From: Vazman@aol.com [mailto:Vazman@aol.com]
Sent: Tuesday, May 25, 2004 1:33 PM
To: ccielab@groupstudy.com
Subject: Frame-relay bytes delayed
I am seeing a lot of bytes delayed and packets delayed when I do a "sh
traffic-shape stat"
Topology is as follows:
Hub (hssi)--FR--(serial) Remote
Hub side has a 6 Mb port speed and remote side has a port speed of 1536K
There are 10 remote sites connected to the FR cloud, either directly to
the Nortel passports or via a T1. All PVC's have a guaranteed rate of
1536K with no bursting. I have FRTS configured only on the hub side as
follows:
int hssi1/0.1
ip add x.x.x.x 255.255.255.252
bandwidth 1536
frame-relay class T1
frame-relay interface-dlci 200
map-class frame-relay T1
frame-relay adaptive-shaping becn
frame-relay cir 1536000
frame-relay bc 192000
frame-relay be 0
frame-relay mincir 1536000
Sh int hssi1/0 showa input rate as 1160K and output rate as 600K but the
bytes/packets delay are still incrementing.
Any suggestions?
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