Hi Martin:
I understand.
why doesn't ABSR-pe check VPNv4 route table to see traffic belong which traffic.
for example , two lsp. take same vpn lable arrived at ABSR-PE. but it is have different RD in vpnv4 route.
when two lsp traffic come back, i know the vpn lable is same. but ABSR-PE can further check VPNV4 destination address in mpls packet and check VPNV4 LFIB to determine the right LSP.
when config ABSR-PE,i can see vpnv4 routes in show ip bgp vpnv4 all.
oh, i know , ABSR-PE don't put this VPNV4 route into route table and LFIB in ABSR-PE,the LFIB don't have this information.
why ABSR-PE don't put vpnv4 bgp routes into route table and LFIB,if ABSR-PE put vpnv4 route LFIB , ABSR can check VPNV4 route to detemine right LSP,like summary in ospf .
oh, i know, sorry,because the return traffic has one vpn label, ABSR first check vpn label, but two lsp may have same vpn lable.
traffic will send to wrong lsp,it is defferent in ospf summary,last label is poped.
(if design option B like this, if ABSR PE receive mpls vpn traffic, ABSR-PE pop the last vpn lable and check vpnv4 route table/LFIB to determine correct next hop and vpn lable(first ABSR-PE must put vpnv4 bgp route into routing table and lfib), but absr-pe will do cef check,not lable switching,it affect performance of ABSR-PE.)
so asbr-pe rewrite vpnv4 lable is a best choice, when vpnv4 lable rewrite ,absr-PE will creat a LFIB, so LFIB entry has one outgoing to other AS vpnv4 lable ,one orginal vpnv4 lable, one orignal next hop label. this is pure lable switching.don't need check vpnv4 routes or cef.
does i understand correctly
thank you,you give me great knowledge.it has been confusing me many days.
oh another question, ASBR-PE will send all VPNV4 routes to other AS, can i limit just only some VPNV4 routes can send to other AS on ASBR-PE. may be i need check some document.
Jun
