topic Re: about traffic shaping in Routing

about traffic shaping

historicalswimming — Sat, 10 Jun 2023 08:37:46 GMT

Could you please give me the simplest configuration to shape all outgoing traffic in cisco iou GNS3 to 20 mpbs ?

Re: about traffic shaping

Joseph W. Doherty — Sat, 10 Jun 2023 10:25:10 GMT

For what device running what IOS?

Re: about traffic shaping

M02@rt37 — Sat, 10 Jun 2023 11:40:48 GMT

Hello @historicalswimming,

Basic config to adapt following your equipement and you case:

interface GigabitEthernet0/0
description LAN interface
ip address 192.168.1.1 255.255.255.0

interface GigabitEthernet0/1
description WAN interface
ip address 100.0.0.1 255.255.255.0
service-policy output SHAPE-TRAFFIC

class-map match-any TRAFFIC
match any

policy-map SHAPE-TRAFFIC
class TRAFFIC
shape average 20000000

--Class-map match any traffic, the service-policy is applied directly to the WAN interface (GigabitEthernet0/1). This ensures that all outgoing traffic on the WAN interface will be shaped to a rate of 20 Mbps.

Re: about traffic shaping

paul driver — Sat, 10 Jun 2023 13:50:34 GMT

Hello
You could apply a simple Hqos policy to traffic shape to 20MB

access-list 1 permit any
class-map all_traffic_cm
match access-group 1

policy_map child_pm
class all_traffic_cm
fair-queue

policy_map parent_pm
class class-default
shape average 20mb
service-policy child_pm

int x/x
description WAN
service-policy output parent_pm

Re: about traffic shaping

Joseph W. Doherty — Sat, 10 Jun 2023 14:39:58 GMT

What M02@rt37 describes would be one way to shape all interface traffic to 20Mbps.

But is it the "simplest" approach? I believe not.

Possibly a simpler CBWFQ policy would be to drop the class-map TRAFFIC, and within the policy-map, use class "class-default" instead.

However, even using CBWFQ assumes your GNS3 device supports it (which it likely does). However, if you truly want the "simplest" shaping, before CBWFQ, there was interface GTS (generic traffic shaping). I recall (?), though the later IOS versions have stopped supporting this, but often IOS being used with GNS3 is an older version.

Definitely, both traffic shaping features were available on many IOS versions, and I would usually recommend using the CBWFQ version, if available, but if you truly want "simplest", I suggest GTS is that.

Re: about traffic shaping

Joseph W. Doherty — Sat, 10 Jun 2023 16:08:18 GMT

Ah, @paul driver reply appears to have been posted while I was composing my prior reply.

Basically, what I wrote in my prior reply, also applies to Paul too.

I.e. For the "simplest configuration" CBWFQ approach, likely:

policy-map SimpleShaper
class class-default
shape average 20000000

interface x
service-policy output SimpleShaper

Possibly the "simplest configuration":

interface x
traffic-shape rate 20000000

If you factor in other considerations, for using a shaper, beyond it being the "simplest configuration", then what both Paul and M02@rt37 have shown, should be considered. For example, Paul's example of using a child policy.