Term
| Public Autonomous System numbers |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Administrative Distance for EBGP |
|
Definition
|
|
Term
| Administrative Distance for IBGP |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is BGPs routing loop avoidance mechanism? |
|
Definition
| Looks for its own AS in updates, if found, it's discarded |
|
|
Term
| To view Neighbor Database, issue this command: |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| after neighbor is configured, Open message is sent. Includes AS#, Router-ID, and Hold Time |
|
|
Term
|
Definition
| Transfers routing info. Includes new routes, withdrawn routes, and path attributes |
|
|
Term
| Keepalive BGP Message Type |
|
Definition
| Keepalives keep neighbor relationships active. 60 second default |
|
|
Term
| Notifications BGP Message Type |
|
Definition
| When problem occurs that causes neighbor relationship to fail, notification is sent |
|
|
Term
|
Definition
| IP address of the neighbor from which the update was received |
|
|
Term
|
Definition
| No peering, router is looking for neighbor |
|
|
Term
|
Definition
|
|
Term
| OpenSent, or Active Peering State |
|
Definition
| Open message sent to establish peering session |
|
|
Term
| OpenConfirm Peering State |
|
Definition
| Router has received reply to open sent msg |
|
|
Term
| Established Peering State |
|
Definition
| BGP peering session successful. |
|
|
Term
| Attributes: Must be recognized by all routers, present in all routing updates, and passed on to other BGP routers |
|
Definition
|
|
Term
| Attributes: Must be recognized by all BGP routers, and passed on to to other routers, but do not need to be present |
|
Definition
|
|
Term
| Might be recognized, but is passed on to other routers |
|
Definition
|
|
Term
| Attributes: Might be recognized, and is NOT passed on to other routers |
|
Definition
Optional Non Transitive
MED |
|
|
Term
|
Definition
Ordered list of ASs;
well-known mandatory |
|
|
Term
|
Definition
How this network was learned:
i = network command
? = redistribution
e = EGP, should not see this one
Well-known mandatory |
|
|
Term
| Local Preference Attribute |
|
Definition
value telling IBGP peers which path to select for traffic leaving the AS.
Default = 100
Well-known Discretionary
Highest Preferred |
|
|
Term
| MED Attribute (Multi-Exit Discriminator) |
|
Definition
Suggests to a neighboring AS which of multiple paths to select
Optional Nontransitive
Lowest Preferred |
|
|
Term
|
Definition
Cisco Proprietary - Local Significance Only
Tells router which of multiple paths to choose to LEAVE the AS
Highest weight Preferred |
|
|
Term
| BGP Path Selection Criteria - list |
|
Definition
1. Choose the route with the highest weight.
2. If weight is not set, choose the route with the highest local preference.
3. Choose routes that this router originated.
4. Choose the path with the shortest Autonomous System path.
5. Choose the path with the lowest origin code (i is lowest, e is next, ? is last).
6. Choose the route with the lowest MED, if the same Autonomous System advertises the possible routes.
7. Choose an EBGP route over an IBGP route.
8. Choose the route through the nearest IGP neighbor as determined by the lowest IGP metric.
9. Choose the oldest route
10. Choose a path through the neighbor with the lowest router ID.
11. Choose a path through the neighbor with the lowest IP address |
|
|
Term
| set default local preference; command |
|
Definition
| bgp default local-preference |
|
|
Term
|
Definition
| R1(config-router)# default-metric |
|
|
Term
| Apply route-map 'MED' to all routes advertised to an EBGP neighbor. |
|
Definition
| neighbor 10.1.1.1 route-map MED out |
|
|
Term
| BGP Authentication using MD5 |
|
Definition
| neighbor {ip-address | peer-group-name} password password |
|
|
Term
|
Definition
|
|
Term
|
Definition
| BGP knows about this route, but isn't advertising. Usually because it's a summarized route |
|
|
Term
|
Definition
| BGP can stop advertising a network flaps too often. dampened for a period of time |
|
|
Term
|
Definition
| BGP knows about this network but doesn't currently have a valid route to it. |
|
|
Term
|
Definition
| Route was advertised into BGP, but it wasn't installed into the routing table, possibly because another Routing Protocol had a better Admin Distance |
|
|
Term
|
Definition
| Aged route - when peer is reestablished it should come back up with * |
|
|
Term
|
Definition
| indicates this route was selected for routing table |
|
|
Term
|
Definition
| learned from IBGP neighbor |
|
|
Term
|
Definition
| BGP learned about route from a network statement |
|
|
Term
| Displays routes that were not entered into routing table |
|
Definition
|
|
Term
| Displays the memory used by various BGP databases, BGP activity stats, and list of neighbors |
|
Definition
|
|
Term
| Displays details about BGP neighbors |
|
Definition
show ip bgp neighbors
if IP add is appended, can be followed by [received | routes | advertised] for more detailed information for a particular neighbor |
|
|
