MultiLink PPP 2xSTM-4

yoeyblack · ‎10-31-2005

Hi.

We have a customer connected over 2xSTM-4, and we would like to load balance over the two links. The main idea is that we would like also to rate limit them to 800Mbit/s , but that seems to be rather difficult when you have two physical interfaces. So we thought perhaps bundling the interfaces togheter in one virtual one, using ML-PPP will solve the problem. I would like to know if anybody has already done such type of configs and how well it performs ?

Or any other idea to solve the problem is welcomed.

Thank,

Yo

Georg Pauwen · ‎10-31-2005

Hello,

you could indeed use multilink and apply a QoS on the Multilink interface limiting the bandwidth to 800K.

The config would look like this:

interface Multilink1

no ip address

service-policy output MULTILINK

ppp multilink

ppp multilink-interleave

multilink-group 1

!

interface Serial0/0

ppp multilink

multilink-group 1

!

interface Serial0/1

ppp multilink

multilink-group 1

!

class-map match-any STM

match access-group 101

!

policy-map MULTILINK

class STM

police cir 800000 bc 16000 be 32000

conform-action transmit

exceed-action drop

Instead of dropping all excess traffic, you could also specify to set a precedence, or check the other options you have available after the 'exceed-action' option...

HTH,

GP

yoeyblack · ‎10-31-2005

Hello GP,

Thanks for your message. But actually I was thinking at a much higher speed. 800 Megabits per second, as the aggregate of two STM-4 are a bit more than 1.2Gbps.

So I'm worried about the performance issues that our GSRs will have to support. Any experience at high speeds?

Thanks,

Otto

Georg Pauwen · ‎10-31-2005

Hello Otto,

sorry about that, I didn't realize these were STM4's. In that case, you could use the 'rate-limit' command under the multilink interface:

interface Multilink1

rate-limit input 840000000 1680000 2520000 conform-action transmit exceed-action drop

The GSR should be able to easily handle that...that said, I have no equipment to test this setup...

HTH,

GP