Per VRF label or Per route label

[romccallum]

Folks,

A few weeks back I saw on some study group somewhere that im on a decent conversation on the downfalls of per vrf labels (juniper) compared to per route label (cisco). Now per route label obviously has its limitations in label consumption but per vrf label threw up a few issues - one of which was something to do with sub optimal routing. Anyone know any downfalls of using per vrf label space?

[Harold Ritter]

Rob,

One of the disadvantages of per VRF label scheme is that it requires an IP lookup on the edge router. This is due to the fact that if the label is shared among all CEs on a given PE, an IP lookup needs to be done in the VRF to determine which CE we should send the label to.

Another disavantage would be that you couldn't support CsC using a per VRF label since an IP table lookup is required on the PE, which breaks the end to end LSP.

On the other hand, you are absolutely right about the increase resources comsumption when a per route label scheme is used. This affects some vendors more than others though.

Hope this helps,

[romccallum]

cheers H. Do you have any docs that list and explain the major draw backs of per vrf label allocation somewhere? or should i contact my account team for that stuff?