Table of Contents
What are attributes of BGP?
BGP attributes are a confusing array of information carried in a BGP update capable of indicating anything from path preference to various additional pieces of information about a route, either within an autonomous system or outside an autonomous system.
What are transitive BGP attributes?
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.
How does BGP use as path attribute?
BGP AS Path Attribute AS Path Attribute is one of the mosth used BGP Path Attribute by Service Providers. In AS Path Attribute mechanism, whenever a route passes an AS (Autonomous System), it adds the number of AS it passed. So, AS Path Attribute is a list of AS numbers, that the router traverse.
Which type of attribute must be recognized by all the BGP implementations?
Discretionary
Discretionary – The attribute must be recognized by ALL implementations but does not have to be included in every BGP UPDATE.
How many BGP path attributes are there?
Four categories of attributes exist as follows: Well-known mandatory: Must be recognized by all BGP routers, present in all BGP updates, and passed on to other BGP routers. For example, AS path, origin, and next hop.
What is origin attribute in BGP?
The origin attribute indicates the origin of a prefix and can take three values: the prefix originates from an interior routing protocol (IGP), it originates from EGP, the predecessor to BGP, or the origin is “incomplete”, if the prefix is learned through “other means”.
What are the two most important BGP attributes?
BGP Attributes
- Well-known mandatory: Must be recognized by all BGP routers, present in all BGP updates, and passed on to other BGP routers.
- Well-known discretionary: Must be recognized by all BGP routers and passed on to other BGP routers but need not be present in an update, for example, local preference.
What order should I learn BGP attributes?
BGP Best Path Algorithm Mnemonic
- Weight (Highest is better)
- LOCAL_PREF (Highest is better)
- Originated Locally.
- AS_PATH (shortest)
- ORIGIN Type (IGP is lower than EGP and EGP is lower than Incomplete)
- MED (lowest is better)
- Paths (External > Internal)
- RID (Router ID – lowest is better)
How do you remember a network?
A great place to keep information regarding your new networking contacts is in your phone’s contacts. Along with adding their name, number and email, add notes. If you learned they went to the same university, write it down. If you learn better by physically writing, take notes on the back of the person’s card.
What is weight attribute in BGP?
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 many path attributes are there in BGP?
This BGP router has 5 paths for network 1.0. 0.0/24….Attributes.
| Priority | Attribute |
|---|---|
| 7 | eBGP path over iBGP path |
| 8 | Shortest IGP path to BGP next hop |
| 9 | Oldest path |
| 10 | Router ID |
What are the well-known mandatory BGP attributes?
Well-known mandatory: Recognized by all BGP peers,passed to all peers,and present in all Update messages.
What does BGP stand for in networking?
BGP stands for Border Gateway Protocol, it is core routing protocol of the Internet which contains a colletions of multiple networks and IP tables.
What is the purpose of BGP?
The main purpose of BGP is to exchange routing updates like other routing protocols, but BGP typically does not exchange individual network routes (but it technically can), it exchanges summaries of network routes. This is because the typical use of BGP is over very large networks including the Internet.
What you should know about BGP’s local_Pref?
Local to an AS.