Traffic shaping between L2 and L3 interfaces.

[tarik.cisco]

Hi everybody !
I have some doubts about how to do traffic shaping !

We have a router Cisco 1900 series (1921), with one 4-port fast Ethernet L2 card (HWIC-4ESW), and two GigabitEthernet ports.

LAN side is connected to HWIC wich is a Layer 2 interface, and the WAN side is connected to Gigabit wich is Layer 3 interface.

The LAN side is connected as trunk and belong to 3 vlan interfaces (Vlan IDs: 20, 30, 40).

The WAN side is connected to Internet link (2Mbps).
I need do the traffic shaping as follow:

Vlan 20 is more critical, I need 1256Kbps
Vlan 30 is for CCTV system, I need 512Kbps
Vlan 40 is for VoIP, I need 256 Kbps or at least 100 Kbps.

The router is located at a Hydreletric Power Plant, wich is remote controled, so the traffic shaping is only for UPLOAD, from LAN side to WAN SIDE.

How can I proceed with this configuration ?? Can anyone help me please ??

thanks !!!!
Tarik Malian

[Sergey Fer · Accepted solution]

Whatever you do, you have to configure traffic shaping only in outbound direction. Therefore you can not do shaping on LAN interfaces inbound. Here you need to create nested policy like this.

class-map VLAN20

     match input-interface VLAN20

class-map VLAN30

     match input-interface VLAN30

class-map VLAN40

     match input-interface VLAN40

policy-map CHILD

     class VLAN20

          bandwidth 1256

     class VLAN30

          bandwidth 512

     class VLAN40

          priority 256

policy-map PARENT

     class class-default

          service-policy CHILD

          shape 2000000

interface Gig 0/x

     service-policy output PARENT

1. You should consider that CCTV and VoIP may use the same protocols and conflict sometimes. LLQ for VoIP is common but it may lead to delays in CCTV.

2. There are a number of parameters in LLQ (policing) and shaping that you need to insert. They depends on what your ISP gives to you.

[Joseph W. Doherty · Accepted solution]

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Posting

What Sergey posted is excellent - some other things to consider:

The total allocated class bandwidths exceed the shaper's bandwidth, so it might complain.  If so, just size to fit.

Class-default wasn't explicitly defined, but it's always present.  Unsure what it assumes for bandwidth when it's implicit.  You might need to explicitly define it with a minimum value for bandwidth.

For your CCTV traffic, you might want to increase queue depth (if supported by this IOS).

If supported by your IOS, you might want to add fair-queue to all your non-LLQ classes.

You might find it difficult to obtain the parameters for your LLQ policer and your PARENT shaper.  If so, try the defaults.

To better support VoIP, you might need to allow for L2 overhead which not all shaper's account for.  If so, reduce your shaper bandwidth between 5 to 15%.

[tarik.cisco]

Thanks for you two !!

The VoIP and CCTV traffic are very controlled, it's only a maximum of 2 simmultaneos call using G.729 codec.

In this case do I need to configure LLQ ?

Where do I configure the LLQ ? Police-map, class-map or interface ?
thanks again

[Sergey Fer · Accepted solution]

Wherever you have VoIP you might want to use LLQ

LLQ is configured by priority keyword inside policy-map CHILD.

[tarik.cisco]

Thanks again Tomorrow I will configure and do the tests !!!