Hello, everyone. IS-IS has a mechanism called the three-way handshake that is enabled on P2P links. It is defined in RFC 5303. The basic mechanism defined in the standard is that each side declaresthe other side to be reachable if a Hello packet is h...

Hello, everyone I've recently began studying IS-IS and I cannot wrap my head around what is happening here. All routers are enabled for IS-IS and their links are configured as P2P. P2 and P4-XR are L1-2 routers. They have an L2 adjacency to share ro...

Hello, everyone. I've read a Cisco Live presentation which explains the identifier (NET) for an IS-IS router the following way: Apparently, the whole Area Address field consists of AFI (this defines how to interpret the rest of the address), IDI, an...

Hello, everyone I've recently began studying IS-IS and I captured one of its messages in Wireshark From what I understand, it uses the original Ethernet format (not Ethernet 2) together with LLC. In the LLC, the SAP is roughly similar to the EtherTy...

Hello, everyone. I understand that OSPFv3 separates links from prefixes and purposely moves the prefix information from T1/T2 LSAs into T8/T9. The RFC states the following: o The Hello packet now contains no address information at all. Rather,...