Term
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Definition
| Is a Path Vector Routing Protocol used to make core routing desitions on the Internet. |
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Term
| What Protocol uses and AD? |
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Definition
| IP TCP 179 and iBGP=20 eBGP=200 |
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Term
| What is the keepalive packet name and what's its timer |
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Definition
| KeepAlive=60 Dead=3x ; Advertizement interval is 30 secs for eBGP and 0 secs for iBGP |
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Term
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Definition
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Term
| How many ASN public and private? |
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Definition
| Total= 65535 Private= 1024 Public= 64511 |
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Term
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Definition
Open
Update
Keepalive
Notification |
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Term
| Types of Tables, Databases? |
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Definition
It keeps a few tables per neighboor
RIB
Adj-RIB-in and Adj-RIB-out |
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Term
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Definition
1- Weight: cisco specific paramenter, default 0
2- Local Preference: 100 by default. Create a route-map: set local-preference 100
3- Routes Originated Locally: network, aggregate or redistribute
4- Path with shortest AS path: Create a route-map: set as-path prepend AS AS AS AS
5- Lowest Origin Code: IGP, EGP, INCOMPLETE
6- Lowest MED: default 0. the value is shared outside the AS. Route-Map: set metric 100
7- eBGP over iBGP: Lower Administrative Distance 20<200
8- Route with nearest IGP neighbor (lowest IGP metric)
9- Oldest Route
10- Neighbor with lowest ID
11- Neighbor with lowest IP address |
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Term
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Definition
Mandatory well-known attributes
Origin - Specifies the router's origin
IGP
EGP
Unknown - Route was redistributed
AS-Path - Sequence of autonomous system numbers through which the route is accessible
Next-Hop - IP address of the next-hop router
Discretionary well-known attributes
Local Preference - Used for consistent routing policy with an autonomous system
Atomic Aggregate - Informs the neighbor autonomous system that the originating router aggregated routes
Nontransitive attributes
Multiexit Discriminator - Used to discriminate between multiple entry point into an autonomous system
Transitive attributes
Aggregator - IP address and autonomous system of the router that performed aggregation Community - Used for route tagging |
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Term
| What is a Route Reflector and why is required? |
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Definition
| To act as a centralized point for iBGP speakers, to reduce the mesh. Creates a Cluster ID and adds adjacent clients. |
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Term
| What is the syncronization rule? |
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Definition
| If the Route is not in the IGP, do not advertize it thru BGP. |
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Term
| When does it use the 0.0.0.0 Router ID? |
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Definition
| When there's no interfaces with IP set up. |
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