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CCNA Recap: Routing Protocols (Distance Vector + Link State)

Distance Vector  & Link State
Interior and Exterior Gateway Protocols

——— Distance Vector ——————
           how far        which way
* good for small
* little configuration
- RIPv2 [IGP]
        - hop count, max 15
     




- EIGRP [IGP]
- neighbor adjacencies
- runs multiple protocols
- (Cisco proprietary
- ietf standard
* summary route distance 5
* internal distance 90
* external 170
        - bandwidth
                - lowest
        - Delay
            - adds those together through all the links it has to traverse
    - bandwidth + delay = feasible distance
    - unicast+multicast - 224.0.0.10
    - only those who need it

I only know what someone else told me.

hello - unreliable, multi
update -reliable uni/multi
ack - un uni
query -reliable uni/multi
reply - reliable un

— Link State ——————
AD = Administrative Distance.
 Are you up or are you down.
- up = get there
- down = no
Not hops but bandwidth cost
* scalable
* consider the speed

[These are also Interior Gateway Protocols]
* OSPF (AD = 110)
        * Enterprise
* IS-IS (AD - 115)
* provider networks
    * FP
    * OTV
        * = cisco proprietary

When adjacencies happen, a router will advertise its entire database, and each router has to have it’s own copy and they have to synchronize.

Not really advertising routes, enabling procol on those interfaces and allow the HELLOs out of them.

Shortest Path First algorithm

You’re not trying to reach the prefix

——LS———
Phase 1: Reliable flooding
 - each node knows the cost to neighbors
- each node knows the entire network topology

Phase 2: Route Calculation
- Dijkstra’s algorithm

========== =========== =========
AS - autonomous system (RFC 1930)
* independent entity, under your control

Unique AS # given by IANA
* who manage IP blocks and root servers

- BGP
    - Most popular!
    - De Facto standard!
    - Routes between one AS to another AS

ISPs have different AS numbers.
Routers know where the different numbers are (BGP, border gateway protocol)

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