[j-nsp] ISIS L1 and L2 adjacency

[Aaron Gould]

https://www.juniper.net/assets/us/en/local/pdf/study-guide/study-guide-jncip
.pdf 

 

page 279 of 708 - shows the topology

 

page 295 and 296 of 708 - begins to speak of a problem with r5 not being
able to become adjacent with r6 and r7 because the NET's area ID portion is
different at Level 1 with r6 and r7.  once changed to 0002 to match r6 and
r7 level 1, everything works.

 

Question, why doesn't this then create an issue with r5 now not having a
matching NET area ID 0001 with r3 and r4 and thus creating the same issue
that we previously saw with r6 and r7, but now with r3 and r4 ?

 

in other words, if the adjaceny problem from r5 to r6 and r7 was because of
a mismatched area ID, then why after changing r5's area ID to 0002 to match
r6 and r7, why didn't this break the adjacencies with r3 and r4 since now r5
deosn't match r3 and r4 area id of 0001 ?

 

-Aaron Gould