https://drive.mindmup.com/map/1Gn1OWFK1RJwIR-k0MZCYTqSb6OVWCink
| SNPA or Subnetwork Point of Attachment | data link layer address used to identify a connection to a subnetwork, such as an Ethernet address |
| Packet or PDUs Protocol Data Unit | Link |
Type 1: IS-IS hello (IIH) PDUs | Broadcast to discover the identity of neighboring IS-IS systems and to determine whether the neighbors are Level 1 or Level 2 intermediate systems
|
Level 1: 01:80:C2:00:00:14 Level 2: 01:80:C2:00:00:15 | |
| Link-state PDUs | Contain information about the state of adjacencies to neighboring IS-IS systems. on PtP links ack by CSNPs |
| Complete sequence number PDUs (CSNPs) | Contain a complete list of all link-state PDUs in the IS-IS database. |
| Partial sequence number PDUs (PSNPs) | Sent multicast by a receiver when it detects that it is missing a link-state PDU (when its link-state PDU database is out of date) |
| DIS Election on Broadcast & multi-access | ptp the priority = 0 |
router with the higher priority Default priority: 64 [ 0 to 127 ] Priority = 0 >> ineligible | |
| Highest priority | |
| priority tie >>> highest SNAP or Mac@ | |
| No backup DIS in IS-IS | |
| pseudo-node ( Bcst Network = router ) | on Broadcast & multi-access |
| all router adv a single link ( not all the adj ) to the pseudo-node | |
| Metric | Link |
| from 1 through 63, or from 1 through 16,777,215 (224 – 1) | |
| Wide metric | https://www.juniper.net/documentation/en_US/junos/topics/concept/isis-wide-metrics.html |
| Reference bandwidth | cost = reference-bandwidth/bandwidth if ref= 100G |