Field | Description |
|---|---|
Tag | Name that identifies the IS-IS area. |
VRF | VRF name. |
IS-IS Level-n Link State Database | Each IS-IS level has a section with Link-State Packet (LSP) information. |
LSPID | Link-state packet identifier in the form of XXXX.XXXX.XXXX.XX-XX. The first six octets (“XXXX.XXXX.XXXX”) are the system identifier of the router that originated the LSP. The next octet is the pseudonode identifier: • When this octet is nonzero, the LSP describes links from a designated router (pseudonode) that creates and floods an LSP that describes all systems attached to the network. This mechanism is similar to a router link-state advertisement (LSA) in OSPF. • When this octet is zero, the LSP is from a nonpseudonode which describes the state of the originating router. The last octet is the LSP number. If the value is 0x00, the entire LSP was carried in one LSP. If there is more data than can fit in a single LSP, the LSP is divided into multiple LSP fragments and each fragment has a different LSP number. An asterisk (*) means the LSP originated on the system where the command was given. |
LSP Seq Num | LSP sequence number. |
LSP Checksum | LSP checksum. |
LSP Holdtime | Amount of time the LSP remains valid (in seconds). An LSP hold time of zero means the LSP was purged and is being removed from the link-state database (LSDB) of all routers. The value indicates how long the purged LSP will stay in the LSDB before being completely removed. |
ATT | Attached bit. A Level-2 IS indicates its attachment to other areas by setting its attached bit in its Level-1 LSP 0. In other words, this is only set for inter-area routes. Level 1-only routers and Level 1-2 routers that have lost connection to other Level 2 routers will use the attach bit to find the closest Level-2 router. They will point a default route to the closest Level-2 router. |
P | Partition repair. A Level-1 area can become partitioned; this bit means the partition can be repaired via use of Level-2 routes. |
OL | Overload bit. Determines whether the IS is congested. When the overload-bit is set in an LSP, other routers will not use this router as a transit router during SPF calculation. Only packets for destinations directly connected to the overloaded router will be sent to this router. |
IS-IS TLV Codepoint | Description | Standard |
|---|---|---|
1 | Area Addresses | ISO 10589 |
2 | IIS Neighbors | ISO 10589 |
3 | ES Neighbors | ISO 10589 |
10 | Authentication | ISO 10589, RFC 6233 |
22 | Extended IS reachability | RFC 5305 |
128 | IP internal reachability | RFC 1195, RFC 5302 |
129 | Protocols supported | RFC 1195 |
130 | IP external reachability | RFC 1195, RFC 5302 |
132 | IP interface address | RFC 1195 |
134 | Traffic engineering router ID | RFC 5305 |
135 | Extended IP reachability | RFC 5305 |
137 | Host name | RFC 5301, RFC 6233 |
222 | Multi IS reachability | RFC 5120 |
229 | Multi topology | RFC 5120 |
232 | IPv6 interface address | RFC 5308 |
235 | Multi IPv4 reachability | RFC 5120 |
236 | IPv6 reachability | RFC 5308 |
237 | Multi IPv6 reachability | RFC 5120 |