Traffic Shaping or Traffic Policing (Rate Limiting)

[kfarrington]

I have a request and I will simplyfy it below :)

SCENARIO :-

I have a router and two LANs. Host-a on LANa sends too much traffic to a server-b on LANb. The two LANs have other client/server apps which are suffering because of of the host-a/server-b traffic. I need to reseve some bandwidth for the host-a/server-b traffic so other client/server users do not get impacted buy the host-a/server-b traffic.

LAN is 100MB and I want to rate the traffic to 10MB. The traffic is not time critical and we dont care if a transfer between them take 10 minutes or 10 hours.

QUESTION :-

Should I use Traffic Shaping or Traffic Policing (Rate-Limiting) to acheive my goal?

Many thx indeed,

Ken

[mheusinger]

Simplified: none of the two :)

First you should identify the real bottleneck:

1) Switch LANa to router

2) Router interface outgoing to LANb

3) Switch LANb to router

4) Router interface outgoing to LANa

In case 1) or 3) is the bottleneck - look for drops on switch interfaces - the problem is best addressed in the switches. And there queueing should solve your problems.

In case this is not possible or 2) or 4) are the case, imho CBWFQ (Class Based Weighted Fair Queueing) would do the job.

Traffic shaping will always throttle the traffic of host A to the configured rate ... even if no other traffic is present. This is achieved through queueing.

Policing will always restrict host A to the configured bandwidth ... even if no other traffic is present. This is achieved through dropping packets.

Queueing however will only restrict A in case there is more load on the interface than it can handle. In a sense it protects one class from another.

So to get the most out of your network I would choose CBWFQ.

regards

Martin