From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Fri Sep 19 2003 - 14:21:17 GMT-3
Let me first say that if this was a real world FRTS scenario you would have problems with serialization delay causing latency. Even if you fragment the voice DLCI both DCLIs share the same physical interface so the data DLCI could cause latency when large packets are sent on it.
Now back to the scenario.
"Assume voice traffic is will be passing over dlci 101, which has 64k link speed. Configure Frame Relay such that there is no latency and packets are not dropped. DLCI 102 has 50% BW of port speed. Configure CIR, Bc and Be accordingly by maintaining Tc's default value and interface queueing default mechanism. Port speed Between r1 and r2 is 256k."
The values given in the solution do not look correct. The scenario said to use the default Tc but they changed the Tc value on the DLCI used for voice. We know that voice should have the smallest Tc value possible (10ms) but it said use the default. The default Tc value is 1/8 of a second for speeds below 640kbps.
The scenario said to give the data DLCI 50% of the port's bandwidth but a DCLI with 64000 CIR and 8000 Be is not correct if you are trying to give the DLCI 128kbps. The values will allow the DLCI to burst up to 128kbps but only if credits are built up. To truly give the DLCI 50% of the ports bandwidth you would need to set the CIR to 128000 with no Be. Also not trying to sound negative but setting min-CIR to equal CIR when adaptive shaping is not turned on tells me whoever came up with the solution doesn't really understand FRTS.
Now the queuing part of this scenario is good. When traffic shaping is enabled on an interface with Frame-Relay encapsulation the default queuing method changes from fair-queue to FIFO.
Rack4R3#sho int s1/0 | in strate
Queueing strategy: weighted fair
Rack4R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Rack4R3(config)#int s1/0
Rack4R3(config-if)#frame traffic-shaping
Rack4R3(config-if)#^Z
Rack4R3#sho int s1/0 | in strate
Queueing strategy: fifo
Rack4R3#
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Danny.Andaluz@triaton-na.com
Sent: Friday, September 19, 2003 8:45 AM
To: bdennis@internetworkexpert.com
Cc: ccielab@groupstudy.com
Subject: RE: FRTS scenario
Brian,
Those are my solutions. I just wanted to get an idea what might be wrong with it. Below are the configs for the actual solution, which I just don't understand. I would definitely be interested in the vSeminar.
Thanks,
Danny
map-class frame-relay voice
frame-relay cir 32000
frame-relay bc 320
frame-relay mincir 32000
no frame-relay adaptive-shaping
!
map-class frame-relay data
frame-relay cir 64000
frame-relay bc 8000
frame-relay be 8000
no frame-relay adaptive-shaping
frame-relay fair-queue
-----Original Message-----
From: Brian Dennis [mailto:bdennis@internetworkexpert.com]
Sent: Friday, September 19, 2003 3:15 AM
To: Andaluz, Danilo, Triaton/NA
Cc: ccielab@groupstudy.com
Subject: RE: FRTS scenario
Danny,
Are those your solutions to the scenario? The solutions are allowing the router to send data at 64kbps for DLCI 101 and 256kbps for DLCI 102. The router will overwhelm the interface since the AR (aka port speed) is 256kbps. Also configuring min-CIR does not do anything if adaptive shaping is not enabled.
Below is a link to a Frame-Relay traffic shaping presentation I developed. Read it over and let me know if you have any questions. It should help clarify FRTS.
http://www.internetworkexpert.com/resources/01700368.htm
If we can get a few people to sign up I'm willing to do a free Frame-Relay traffic shaping vSeminar next week.
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Danny.Andaluz@triaton-na.com
Sent: Thursday, September 18, 2003 9:03 PM
To: ccielab@groupstudy.com
Subject: FRTS scenario
Hello Group,
A scenario for FRTS on a lab that I'm doing states:
"Assume voice traffic is will be passing over dlci 101, which has 64k link speed. Configure Frame Relay such that there is no latency and packets are not dropped. DLCI 102 has 50% BW of port speed. Configure CIR, Bc and Be accordingly by maintaining Tc's default value and interface queueing default mechanism. Port speed Between r1 and r2 is 256k."
R1
|
| |
dlci 101 | | dlci 102
| |
|
R2
Here's what I have as far as configs. I get all sorts of different answers for what this should be. Hopefully I can get this cleared up. You think you understand something, and then you get punched in the mouth.
Thanks,
Danny
R1
interface Serial0.8 point-to-point
ip address 172.16.78.1 255.255.255.252
frame-relay interface-dlci 101
class Voice
!
interface Serial0.9 point-to-point
ip address 172.16.78.5 255.255.255.252
frame-relay interface-dlci 102
class Data
map-class frame-relay Voice
frame-relay cir 64000
frame-relay bc 640
frame-relay be 0
frame-relay mincir 64000
no frame-relay adaptive-shaping
frame-relay fair-queue
frame-relay fragment 80
!
map-class frame-relay Data
frame-relay cir 256000
frame-relay bc 32000
frame-relay be 0
frame-relay mincir 128000
no frame-relay adaptive-shaping
frame-relay fair-queue
R2
interface Serial0.2 point-to-point
ip address 172.16.78.2 255.255.255.252
frame-relay interface-dlci 101
class voice
!
interface Serial0.3 point-to-point
ip address 172.16.78.6 255.255.255.252
frame-relay interface-dlci 102
class data
map-class frame-relay voice
frame-relay cir 64000
frame-relay bc 640
frame-relay be 0
no frame-relay adaptive-shaping
frame-relay fair-queue
frame-relay fragment 80
!
map-class frame-relay data
frame-relay cir 256000
frame-relay bc 32000
frame-relay be 0
no frame-relay adaptive-shaping
frame-relay fair-queue
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