- CCNP Routing – Forwarding of packets from one network to another network choosing the best path from the routing table.
- Routing makes possible for two or more different networks to communicate with each other.
- Routing table consists of only the best routes for every destination.
- The Administrator configures it manually.
- Mandatory need for the Destination Network ID
- Used for Small organizations
- Administrative distance for Static Route is 0 or 1.
- Advantages of static routing
- There is no overhead on the router CPU
- There is no bandwidth usage between routers
- It adds security because the administrator can choose to allow routing access to certain networks only
- Disadvantages of static routing
- Used for a small network. (It’s not feasible in large networks)
- Each and every network has to be manually configured
- The administrator must really understand the internetwork and how each router is connected in order to configure routes correctly.
- Any changes in the internetwork have to be updated in all routers
- The default route is used when the destination is unknown (Internet)
- Also can be used at end locations where there is only one exit path for any destination
- Last preferred route in the routing table
- Default routes help in reducing the size of your routing table.
- If the routers do not found an entry for the destination network in a routing table, the router will forward the packet to its default route.
Advantages of dynamic over static
- There is no need to know the destination networks.
- Need to advertise the directly connected networks.
- Updates the topology changes dynamically.
- Administrative work is reduced
- Used for large organizations.
- Neighbor routers exchange routing information and build the routing table automatically.
- This is easier than using static or default routing
Types of Dynamic Routing Protocols
- Distance Vector Protocol
- Link State Protocol
- Hybrid Protocol (Advanced Distance Vector Protocol)
Distance Vector Protocol
Link State Protocol
|Works with Bellman-Ford algorithm||Works with Dijkstra algorithm||Works with a DUAL algorithm|
|Periodic updates||Incremental updates||Incremental updates|
|Classful routing protocols||Classless routing protocol||Classless routing protocol|
|Full Routing tables are exchanged||Missing routes are exchanged||Missing routes are exchanged|
|Updates are through broadcast||Updates are through multicast||Updates are through multicast|
|E.g., RIPv1, RIPv2, IGRP||E.g., OSPF, IS-IS||E.g., EIGRP|
|–||Link state updates||Advance Distance Vector Protocol|
- Classful Protocols
- Classful routing protocol does not carry the subnet mask information along with updates
- This means all devices in the network must use the same subnet mask
- E.g., RIPv1, IGRP
- Classless Protocols
- Classful routing protocol carries the subnet mask information along with updates
- This is the reason they support sub-networks & default networks
- E.g., RIPv2, EIGRP, OSPF, and IS-IS
- Administrative Distance
- It is the trustworthiness of the information received by the router.
- The Number is between 0 and 255
- Least value is more preferred.
- Default administrative distances are as follows:
- Directly Connected = 0
- Static Route = 1
- IGRP = 100
- OSPF = 110
- RIP = 120
- EIGRP = 90/170
- IS-IS = 115
- An Autonomous System is a collection of networks under a common administrative domain
- A unique number identifying the Routing domain of the routers.
- Ranges from 1- 65535
- Public from 1 – 64512
- Private from 64513 – 65535
- Private AS is used within the same service providers
- Public AS is used in between multiple service providers
|Interior Gateway Protocol||Exterior Gateway Protocol|
|Routing protocols used within the same autonomous system number||The routing protocol used between different autonomous systems|
|All routers will be routed within the same Autonomous boundary||Routers in different AS need an EGP|
|E.g., RIP, IGRP, EIGRP, OSPF, IS-IS||E.g., BGP – Border Gateway Protocol|