As shown in the exhibit, you have an LSP established from R1 to R4. Your network experiences a link failure between R2 and R3.Which statement is correct?
A.
A ResvTear message is sent toward the egress router.
B.
A ResvConf message is sent toward the ingress router.
C.
A PathErr message is sent toward the egress router.
D.
A ResvTear message is sent toward the ingress router.
I think Option D is the correct one.
The idea behind it that Path error messages are sent toward the ingress router, while RESV tear messages are sent towards ingress router
Reference
http://www.juniper.net/techpubs/en_US/junos9.5/information-products/topic-collections/config-guide-mpls-applications/id-16985.html
The correct reference is
http://www.juniper.net/techpubs/en_US/junos9.6/information-products/topic-collections/nog-mpls-logs/rsvp-resvtear-message-examining.html
Due to it D is incorrect, and the A is correct.
PS: got this question in practice test, so A is 100% correct.
According to your link the ingress router receives ResvTear message, so D is correct.
i2e -> path, pathtear, resverr, resvconf
e2i ->resv, resvtear, patherr
Here is what will happen guys:
Transit packets begin to drop at the instant that the link between R2 and R3 fails.
In response to the link failure, R3 will send a ResvTear message upstream to R2.
R2 will, in turn, send a ResvTear upstream to R1.
So D is correct 🙂
how is it possible to send from R3 to R2 when there is no link??! 😉