Which BGP attribute is optional and non-transitive?
BGP path attributes
| Name | Category |
|---|---|
| ATOMIC_AGGREGATE | Well-known discretionary |
| COMMUNITY | Optional transitive |
| MULTI_EXIT_DISC (MED) | Optional non-transitive |
| ORIGINATOR_ID | Optional non-transitive |
What is non-transitive attributes BGP?
Transitive BGP Attributes are ALLOWED to be sent to other peers. BGP Non-Transitive Attributes are NOT allowed to be sent to other peers. For example, BGP community strings are an optional transitive attribute as in if you receive an update containing a community string then you can pass it on to your other neighbors.
Which two BGP attributes are optional non-transitive attributes?
BGP Attributes are pieces of information that a BGP router attaches to describe different prefixes included in it’s BGP update messages….BGP Attributes list:
| Type Code value | Attribute Name | Attribute Type |
|---|---|---|
| 14 | Multiprotocol Reachable NLRI | Optional non-transitive |
| 15 | Multiprotocol Unreachable NLRI | Optional non-transitive |
What are different BGP attributes?
There are four well known BGP communities: Internet: Prefix can be advertised to all BGP neighbors. No-Advertise: Prefix should not be advertised to any BGP neighbors. No-Export: Prefix should not be advertised to any External BGP neighbors.
What are three well known mandatory BGP attributes?
BGP Path Attributes
- Well-Known Mandatory (for example: Origin, AS Path, and Next Hop)
- Well-Known Discretionary (for example: Local Preference)
- Optional Transitive (for example: Community)
- Optional Non-Transitive (for example: Cluster List)
What is BGP weight attribute?
The BGP Weight Attribute Weight is a value that is assigned to our prefixes as a locally significant value. Weight is a simple number in the range of 0 through 65535, and the higher the weight value, the higher the preference for that path. When the prefix is locally generated, it will get a weight of 32768.
How do I set BGP attributes?
BGP Table path selection
- Prefer the highest local-preference value.
- Prefer the shortest AS-path length.
- Prefer the lowest origin value.
- Prefer the lowest MED value.
- Prefer routes learned from an EBGP peer over an IBGP peer.
- Prefer best exit from AS.
- For EBGP-received routes, prefer the current active route.
What is BGP MED attribute?
The BGP MED attribute, commonly referred to as the BGP metric, provides a means to convey to a neighboring Autonomous System (AS) a preferred entry point into the local AS. BGP MED is a non-transitive optional attribute and thus the receiving AS cannot propagate it across its AS borders.
Is Med a transitive attribute?
The BGP multiple exit discriminator (MED, or MULTI_EXIT_DISC) is a non-transitive attribute, meaning that it is not propagated throughout the Internet, but only to adjacent autonomous systems (ASs). The MED attribute is optional, meaning that it is not always sent with the BGP updates.
How is Med used in BGP?
MED (or metric) is the sixth BGP attribute: MED can be used to advertise to your neighbors how they should enter your AS. MED is exchanged between autonomous systems. MED is propagated to all routers within the neighbor AS but not passed along any other autonomous systems.