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23 Cards in this Set
- Front
- Back
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- What is an IP prefix?
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- It refers to the IP subnets assigned to networks by the official governing body that manages IP addresses.
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- Full feed refers to what?
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- To all internet prefixes
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- What is a BGP feed?
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- BGP session that provides reach ability information of IP prefixes on the Internet
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- Router ID (RID)?
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- It’s the highest loopback IP address
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- Exit point
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- This is a router that connects two autonomous systems; traffic comes in and goes of the internet through the exit point.
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- EBGP is primarily used in two different environments
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- Between ISP’s and their customers
- Between different ISP’s |
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- What is an Internet exchange point?
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- It's where all the big ISPs exchange BGP routes with each other.
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- Name 3 types of BGP peering agreements
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- Transit; If B is configured so that it will pass all internet traffic from A, B is a transit provider of A.
- Public; An EBGP session at IXP - Private; An EBGP session on a private link between two autonomous systems is called private peering. |
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- What transport mechanism does BGP relies on to establish its connection and to exchange information between BGP peers?
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- TCP port 179
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- What is the requirement needed before any information can be exchanged between BGP speakers
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- A neighbor relationship
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- What does BGP use to ensure availability of BGP neighbors?
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- Keep alive messages
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- What are the 6 stages of neighbor relationship?
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- Idle;
- Connect; BGP waits for a TCP connection to be completed - Active; TCP connection is initiated - Open Sent; - Open Confirm; - Establish; |
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- 2 types of configurations when peering with EBGP
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- Peering with a physical interface
- Peering with each others loopback Interface |
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- Loopback addresses are used because.....
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- They are virtual interfaces and they never go down like physical interfaces do
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- Three ways to advertise the prefix
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- Using the network statement
- Using the redistribute command - Using the aggregate statement |
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- What are BGP policies?
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- They influence how traffic flow coming in or going out of the network
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- What is an IP prefix?
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- Refers to the IP subnet assigned to networks by the official governing body that manages IP address.
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- What is a Hot Potato?
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- BGP policy that governs that traffic will exit the AS from the closest exit-point router
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- What is a Cold Potato?
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- BGP policy that governs that traffic will be delivered through the path that is closest to the destination.
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- What does BGP use to ensure availability of BGP neighbors?
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- Keepalives
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- What is the holdtime value for keepalives?
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- 90 seconds
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- What are the 2 ways to configure peering EBGP?
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- Peering with the physical interface
- Peering with each other’s loopback interfaces (with static routes used to reach the other loopback address) |
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- Why do we use loopback addresses?
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- Because they are virtual interfaces, they never go down like physical interfaces do.
- Even if one physical interface goes down, BGP between loopback remains up as long as they exist as redundant paths to each other’s loopbacks. |
