MPLS - Frame Relay Traffic Shaping

We recently upgraded from 3 T1 circuits (4.5MB) to 5 T1 circuits (7.5MB) at the office. During the upgrade we experienced some high latency issues. These issues might have already existed, but were overlooked. With the ISP on the phone during the setup, they were the ones who caught it.

The config is as followed:

!
interface MFR1
description connected to MPLS
no ip address
frame-relay traffic-shaping
frame-relay lmi-type ansi
!
interface MFR1.682 point-to-point
bandwidth 4608
ip address x.x.x.x 255.255.255.252 *IP removed for forum
frame-relay interface-dlci 682 IETF
class SD
!

...

!
map-class frame-relay SD
frame-relay cir 4608000
frame-relay mincir 4608000
service-policy output SD-VoIP
!


The ISP engineer informed me to remove the following lines:
frame-relay traffic-shaping
class SD

New config:

!
interface MFR1
description connected to MPLS
no ip address
frame-relay lmi-type ansi
!
interface MFR1.682 point-to-point
bandwidth 7680
ip address x.x.x.x 255.255.255.252 *IP removed for forum
frame-relay interface-dlci 735 IETF
!

...

!
map-class frame-relay SD
frame-relay cir 7680000
frame-relay mincir 7680000
service-policy output SD-VoIP
!


From what I understand, the Frame-Relay traffic shaping is designed to control the amount of traffic the router sends out a specific interface or particular DLCI. My question is, why would this command have caused such high latency? We are talking close to 1000ms. Once that was removed, the latency dropped. But the class still exists. I'm just a little confused on how it works.


Cheers,

ZiPPy

Hmm, Could I see the SD-VoIP policy?

Frame-relay traffic-shaping is put on primary interface to allow you to apply specific policy to a sub interface.

The "class SD" applied the below to the interface.

The:
map-class frame-relay SD
frame-relay cir 7680000
frame-relay mincir 7680000
service-policy output SD-VoIP

is no longer applied to that interface, so it no longer effects the traffic. What bothers me about this being removed is it looks like you also striped it of its VoIP QoS.

This raises a great amount of suspicions if QoS is working or not. Secondly, I need to find how to put the 'class SD' back into the configuration. Simply adding the 'class SD' line back into the router will crash it. How do I know this? Because I did it.

I'm currently investigating the issue.


ZiPPy

I would revise the bandwidth values in the following lines:

[code:1]bandwidth 4608

map-class frame-relay SD
frame-relay cir 4608000
frame-relay mincir 4608000[/code:1]

4608 means 4608kbps, and 4608000 means 4608000bps. It's looks like these are the old speeds for the 3 T1 circuits (4.5Mbps = 1024 X 4.5). Try to changing them to 7680 and 7680000 (i.e 7.5bps = 1024 X 7.5). So the lines would be:

[code:1]bandwidth 7680

map-class frame-relay SD
frame-relay cir 7680000
frame-relay mincir 7680000 [/code:1]


Just a guess, there might be other things too.

I totally agree S0lo, but I already have the frame-relay cir 7680000 set, as you can see from Kajitora's post.

My question at hand right now is how removing the 'class SD' ties in to everything, and why placing it back into the config crashes the router.


This VoIP stuff is an entirely different world, yet this is all part of the Routing & Switching environment. I need to read up more and research this more in-depth. Still have something fishy going on, but not big enough to break the entire system.

Working on it...


ZiPPy

ZiPPy,

Silly I didn't see that 7680000 above :oops:. I better stop posting at bed time.