Per Packet load Balancing in Cisco Switches

[RAMACHANDRA R]

Hi Team,

Can we enable per packet load balancing/sharing in cisco 3560 and 4948 Switches ? I can see two routes are installed in routing table for a destination prefix but for traffic to specific destination is not going across both the link. The option what i am getting  in command line is ip load-sharing per-destination but not  ip load-sharing per-packet.

Please do let me know is there any option to do per-packet load balancing

I have tried disabling route-cache, cef etc.. no result.

Rgds

Rama

[schooram]

Hi Ramachandra,

On both these platforms per packet load balancing is not surpported.  it is a feature mostly seen in routers.

it can use the following variables for the load sharing hash  (but the per packet is never used)
 
Source ip
Dest ip
Source tcp port 
Dest tcp port

so you can configure flow based sharing based on above parameters on both the switches.

The more random variables going into the hash equation the more likely of an even distribution across links. 
The src/dst ports in the equation gives us this randomization. If the same (static) variables go into the hash, the
same link is chosen.

Follow this link for more details:
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/25sg/configuration/guide/cef.html#wp1150531

cheers,
sandeep 

[RAMACHANDRA R]

Thanks Sandeep,

Is there any other way where we can push the traffic on these links

Rgds

Rama

[24madaeve1]

hi there. I have one doubt pertaining to per-packet load-sharing. In order to connect my two remote sites- A & B, Site A is having two WAN links and Site B is having two WAN links - one from ISP1 (30Mbps link) and the other from ISP2 (50Mbps link). I am doing static route load balancing using same AD values for both the ISPs. I have configured "ip load-sharing per-packet" on both the outgoing interfaces.

The load is getting distributed equally across both the links but total bandwidth utilization across both the links is not going beyond 30Mbps. The combined bandwidth of both links is 80Mbps (50+30). However links are not getting fully utilized even though heavy load is there on the links. Can you please tell me how to make full use of both the wan links at both the ends?