Unicast Routing Protocols

auos

Why (EIGRP and OSPF) are Unicast Routing Protocols.

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Comments

burbankmarc

They are used to direct data to a specific host. PIM is a multicast routing protocol used to direct data to more than one host.

billscott92787

auos wrote: »

Why (EIGRP and OSPF) are Unicast Routing Protocols.

Once you start digging into it you will understand it a little more. Just like burbankmarc stated you have PIM, within that you have PIM Sparse and PIM dense. Deciding which one to use depends on many factors. From what I have read so far when deciding

PIM Dense is better in the following sitations:

- The multicast group and recipients are physically close.
- There will be few senders, and many receivers
- All routers in the network have the capability to forward multicast traffic.
- There will be a great deal of multicast traffic
- The multicast streams will be constant

Whereas PIM Sparse is better in the following situations:

- The multicast routers are widely dispersed over the network.
- There are multiple simultaneous multicast streams
- There are few receivers in each group.
- The multicast traffic will be intermittent.

Remember also that PIM Sparse uses a RP (or Renedzvous Point) for it's root, whereas PIM Dense does not. I believe also that PIM Dense creates its tree from the root done, whereas builds it from the nodes up to the root. Just a few differences. I got most of this information from Chris Bryant's Train Signal BSCI videos.

Also, which I do not believe this is an NDA violation or it wouldn't be allowed to be said in his videos, it is known that configuring the MOSPF or DVMRP (which uses a Type of RIP), is beyond the scope of the BSCI, but always can't hurt to learn more (especially if you plan to tackle the CCIE one day).

Forsaken_GA

I think his confusion stems from the fact that they communicate over multicast, but they're called unicast routing protocols.

They're unicast routing protocols because they move unicast traffic, multicast traffic is handled by other protocols

abdulwart

I know that both Eigrp and OSPF are using Multicast addressing to discover neighbors and that might be the answer for your question, although you mentioned Unicast.

Eigrp uses 224.0.0.10 to discover the neighbors but OSPF uses two multicast address 224.0.0.6 and 224.0.0.5

abdulwart

just went throught Eigrp and as you may know, EIGRP has the features of:

1- Support multiple path (Equal and unequal)
2- RTP (Reliable trasmission Protocol)
3- Supports VLSM
4- Dependable Protocol

What I am mentioning here is the RTP Protocol. EIGRP is reliable (sends unicast packets) when it comes to Reply, Quary, Update packets, however, for the Hello and the ACK packets EIGRP does not need to use unicast addressing instead, it uses Multicast addressing using IP address 224.0.0.10

Regarding the OSPF, OSPF is reliable Protocol and it does not use the TCP/IP Ack for that, instead, it uses its own ACK and that is why it is Unicasting protocol.

Hope that expalining it.