CEF

[nw301]

Want to know if there are any limitations to using CEF.

I have two T1 and want to bond them is there any issues with reordering of packets.

[wkumari]

CEF can run in either per-packet or per-destination mode.... Here is a link:

http://www.cisco.com/en/US/customer/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca62c.html#xtocid237123

[nw301]

I should explain myself better. I understand the mode for CEF but, are there applications that are effected by it.

i.e... VPN tunnels, Citrix sessions, Terminal services, Cache Engines.

[wkumari]

If you run CEF in per-destination, then packets destined to a specific IP should always go through the same interface (unless it goes down!). This means that the load balancing should be transparent to the devices being load-balanced. If a large percentage of your traffic is between a few IP addresses then per-destination may not give you very equal balancing (eg If all of your traffic goes accross a single VPN then you will only use 1 link).

Per packet will do round-robin over the links, but if your links have different delays you may run into some issues with varous things (VoIP, VPN, PC Anywhere, tcp slowness, etc)

Stick with per-destination mode inless you have a compelling reason not to.

--Warren