Routing Protocol Code

Routing is the process of moving packets across a network from one host to another host by using the best path from the router table. In other words, it may also be defined as the process of selecting a specific path for a traffic in a network or across multiple networks. It is performed by network layer devices in order to deliver the packet by choosing an optimal path from one network to another network.

Routing can be classified into three types: Static Routing, Dynamic Routing, Default Routing (explained below). 

Types of Routing:

1. Static Routing: Static Routing is a process of adding routes to the routing table manually by users.

• It is configured by the Administrator manually.
• Mandatory need of the destination Network ID.wri
• It is secure and fast.
• The administrative distance for static is 0 and 1.
• Generally used for a small organization with a network of 10-15 routers.
• For large network size (100 or above), it becomes hectic for an administration to manually add route for the network.

2. Dynamic Routing: Dynamic routing automatically makes adjustments to the routes according to the topology of the network or the current state of the route in the routing table.

• works with advertisements of directly connected networks.
• updates the topology changes dynamically.
• used for large organizations.
• Neighbor routers exchanges routing information and build the routing table automatically.

3. Default Routing:  This protocol is configured for unknown destinations. This is the method where the router is configured to send all the packets forwards to a single router.

• It is the last preferred routing.
• helps in reducing the overall size of the routing table.

 Routing Protocols:

Dynamic routing protocols use metric, cost, and hop count to justify the best path from the possible paths available for the destination network. There are 3 types of routing protocols.

• Distance Vector protocol.
• Link state Routing Protocol.
• Advanced Distance vector routing protocol.

For more details please refer to Classes of Routing Protocols article.

Steps to Find Routing Protocol Codes:

• Open cisco packet tracer.
• Then, select any router and in CLI command.
• Type show IP route.

Different Protocol Codes:

S.No.	Symbol	Code Name	Description
1	L –	local	Local routes are employed by the routing table to efficiently process packets with a destination address of the interface of the router.
2	C –	Connected	Identifies a directly connected network.
3	S –	Static	It occurs when a router uses a manually configured routing entry.
4	R –	RIP	A routing protocol is typically used as an Interior Gateway Protocol.
5	M –	mobile	Allows the users to maneuver from one network to a different one.
6	B –	BGP	It manages how packets will get routed from one network to another.
7	D –	EIGRP	The advanced distance-vector routing protocol is used on a computer network for automating routing decisions and configuration.
8	EX –	EIGRP external	The route that was redistributed into EIGRP.
9	O –	OSPF	It is an intradomain protocol, which suggests that it’s used within a neighborhood or a network.
10	IA –	OSPF inter area	Routes are flagged as O IA in the show IP route command output.
11	N1 –	OSPF NSSA external type 1
12	N2 –	OSPF NSSA external type 2
13	E1 –	OSPF external type 1	Add up the value of every link to the ASBR originating.
14	E2 –	OSPF external type 2	Type 2 will not, and just use the metric that it originates.
15	i –	IS-IS	Designed to maneuver information efficiently within a network.
16	su –	IS-IS summary	Shows the summary of IS-IS areas.
17	L1 –	IS-IS level 1	Link-state the network information of its own area for all the intra-area topology.
18	L2 –	IS-IS level 2	The link-state information for the intra-area is also as inter-area routing.
19	ia –	IS-IS inter-area	Routing between areas is organized hierarchically.
20	* –	candidate default	A prefix that will be used as a default route.
21	o –	ODR	It is a way to share routes in a basic hub and spoke network.
22	P –	periodic downloaded static route	Routes can be dynamically downloaded from an AAA server by the network access servers.
23	H –	NHRP	It works as a route source and installs shortcut paths as NHRP routes directly into the Routing Information Base.
24	l –	LISP	Routing and addressing architecture of the web Protocol.
25	+ –	replicated route	Instance to duplicate routes from the general public network or other VPN instances.
26	% –	next hope override	NHRP overrides the other protocol’s next-hop entries by installing shortcut next-hops in the RIBnext-hop network.