Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.


multilayer switching MLS-RP,8 bit Xtag value

Hi everybody

How is everyone doing?

I was reading about multilayer switching of past days.  This is what my book says about " 8 bit Xtag value" :

"In an environment where multiple MLS-RPs are present, the MLS-SE must be able to differentiate

between each MLS-RP. This can be done based upon the MAC address of each MLS-RP; however,

if there are thousands of flow entries in the MLS cache and if each of the entries associated with an

MLS-RP that has just gone down need to be flushed, searching through the cache based upon a

48-bit MAC address value can take some time. To facilitate faster cache purges, an 8-bit XTAG

value is assigned to MLS-RP, which acts like an index for each MLS-RP, allowing the MLS-SE to

differentiate between the flow entries associated with each MLS-RP much more quickly."

So xtagvalue basically allows switch to locate entries faster. But when I look at the contents of mls cache, as shown below,I don't see any xtag value.

Switch-A> (enable) show mls entry ip

                                  Last    Used

Destination IP  Source IP       Prot DstPrt SrcPrt Destination Mac   Vlan Port

--------------- --------------- ---- ------ ------ ----------------- ---- -----


No entries

MLS-RP   -    -      -      00-10-a4-e0-1e-d3 1    2/2   -    -      -      00-06-53-fe-84-20 2    2/3

Any help will be greatly appreciated.

thanks and have a great week ( It is almost over thanks God!)

CreatePlease login to create content