From: MMoniz (ccie2002@tampabay.rr.com)
Date: Sat Jul 19 2003 - 11:52:48 GMT-3
Well this is because of serialization on lower speed frame circuits. Since
you do not want
voice packets delayed more than 20 ms, you must break up data frames to
accompnay this.
Since the CIR is 192, you need to break up packets to 240 so voice packets
are not delayed
more than 20 ms.
Here is a chart and a link.
Lowest Link Speed in Path
Recommended Fragmentation Size
56 Kbps 70 bytes
64 Kbps 80 bytes
128 Kbps 160 bytes
192 would be right here which would be a frag size of
240
256 Kbps 320 bytes
512 Kbps 640 bytes
768 Kbps 1000 bytes
1536 Kbps 1600 bytes
http://www.cisco.com/en/US/customer/tech/tk652/tk698/technologies_configurat
ion_example09186a0080094af9.shtml#topic4
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Jason Cash
Sent: Thursday, July 17, 2003 11:32 PM
To: ccielab@groupstudy.com
Subject: Map-class frame-relay - values and commands
Can someone tell me how the '240' was arrived at for the 'frame fragments'?
map-class frame-relay frts_R5
frame-relay cir 192000
frame-relay bc 1920
frame-relay be 0
frame-relay mincir 192000
no frame-relay adaptive-shaping
frame-relay fair-queue
frame-relay fragment 240
frame-relay ip rtp priority 16384 16383 48
The task instructs:
Assume that the link speed of R2 is 512kbps where 50% is dedicated to R4 &
remaining is for R5 & R6. The link speed of R5 is 192 kbps & R6 has 64kbps.
The traffic crossing link will be voice.
Also, I am running 12.1(20) on a 2500 and 'frame ip rtp and 'frame
fragments' is not available. Any suggeestions?
r5(config-map-class)#frame-relay ?
adaptive-shaping Adaptive traffic rate adjustment, Default = none
bc Committed burst size (Bc), Default = 56000 bits
be Excess burst size (Be), Default = 0 bits
cir Committed Information Rate (CIR), Default = 56000 bps
custom-queue-list VC custom queueing
end-to-end Configure frame-relay end-to-end VC parameters
fair-queue VC fair queueing
fecn-adapt Enable Traffic Shaping reflection of FECN as BECN
idle-timer Idle timeout for a SVC, Default = 120 sec
mincir Minimum acceptable CIR, Default = CIR/2 bps
priority-group VC priority queueing
traffic-rate VC traffic rate
This archive was generated by hypermail 2.1.4 : Wed Aug 06 2003 - 06:52:45 GMT-3