Comments on: frame relay traffic shaping

By: arul

arul — Tue, 15 Jun 2010 13:32:23 +0000

For the bandwidth command, assume that i have a remote site (F.R with speed 256kbps), and i applied the following at the remote site router:
policy-map shaping
class one
bandwidth percent 30
class two
bandwidth percent 30
class three
bandwidth percent 10
class class-default
fair-queue
And applied this policy at the interface (out), when i issued the show policy-map interface ….
router#show policy-map interface serial 0/0/0
Serial0/0/0
Service-policy output: testing
Class-map: one (match-all)
0 packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol http
Queueing
Output Queue: Conversation 265
Bandwidth 30 (%)
Bandwidth 463 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: two (match-all)
0 packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol ftp
Queueing
Output Queue: Conversation 266
Bandwidth 30 (%)
Bandwidth 463 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: three (match-all)
0 packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol dns
Queueing
Output Queue: Conversation 267
Bandwidth 10 (%)
Bandwidth 154 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: class-default (match-any)
5 packets, 185 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 256
(total queued/total drops/no-buffer drops) 0/0/0
You see 30% of the bandwidth is 463kbps which means the available banwidth 1543 kbps.
————-
If we set the bandwidth command to 256
it looks like
router#show policy-map interface serial 0/0/0
Serial0/0/0
Service-policy output: testing
Class-map: one (match-all)
0 packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol http
Queueing
Output Queue: Conversation 73
Bandwidth 30 (%)
Bandwidth 76 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: two (match-all)
0 packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol ftp
Queueing
Output Queue: Conversation 74
Bandwidth 30 (%)
Bandwidth 76 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: three (match-all)
packets, 0 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: protocol dns
Queueing
Output Queue: Conversation 75
Bandwidth 10 (%)
Bandwidth 25 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: class-default (match-any)
35 packets, 1045 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 64
(total queued/total drops/no-buffer drops) 0/0/0
which is right?
My question if we missed the banwidth command the configuration will be correct?

By: Kumar

Kumar — Tue, 15 Jun 2010 13:30:04 +0000

1. The frame carrier’s CIR is the guaranteed bandwidth for your connection. You could order a T-1 Port with a 768K CIR. The provider will guarantee you 768K. Anything sent above that would be discard eligible. Obviously, you can burst past the CIR,
2. CIR is the speed at which you want to send traffic out of an interface. For example, if you have one site with T-1 access sending to a site with 256K access, you want to send at 256K from the T-1 site. Otherwise the 256K end gets overrun. All FRTS is doing is delaying traffic. FRTS sends traffic in intervals which you configure. If no space is available in one interval, traffic must wait for the next interval. That is a great link that was posted above.
And yes, Bandwidth and CIR are not related. BW is used for certain routing protocol metrics (EIGRP, IGRP, OSPF). And CIR is the speed at which you want to send traffic. If you’re nesting a policy map inside of a frame map class it will use the interface bandwidth for certain settings within the policy map.

By: arul

arul — Tue, 15 Jun 2010 13:29:32 +0000

The traffic-shaping parameter definition at both end need not be the same, right?

Thanks again.

By: Kumar

Kumar — Tue, 15 Jun 2010 13:28:49 +0000

the bandwidth command configured on an interface and the CIR are not related, the bandwidth command is usually configured for routing protocols such as EIGRP.
As for GTS (Generic Traffic Shaping), you can inded use that for Frame Relay as well. Check the following document for a discussion and when you would use GTS and when FRTS:
Traffic Shaping
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800bd8ed.html#wp1001072

By: Kumar

Kumar — Tue, 15 Jun 2010 13:27:34 +0000

Thanks very much.

I was wondering though. When is generic traffic shaping used?

Thanks again.