RIP - Least possible Hop Count

I have a basic doubt on RIP. My friend just told me that the minimum hop count for the RIP is 1 and maximum is 15, which I got confirmed from the following cisco page

www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/rip.htm

But the article on Distance Vector Routing Protocol ( www.firewall.cx/distance_vector.php ) says the if a network is directly connected to the router's interface then it will have a hop count value of zero(0) in the router's table entry.

Since RIP works on the principle of Distance Vector Routing Protocol, I thought that RIP too will have a minimum hop count value of zero(0). But this is not the case.

Can anyone clarify on this.

Hmm, interesting. Appologies as this isn't yet an area of expertise (currently studying for CCNP).

Anyhow, since RIP is for dynamically updating routing information in routers, would RIP be classed as being applied for local subnets that are physically connected to the router. Surely the RIP packets are sent to neighbouring routers and thus would have a setting of 1 when sent through to the routers one hop away ?

Just a though ?

Cheers

I think you are mixing up hop count with administrative distance values:

0= directly connected
1= static route
100= IGRP
120= RIP
etc etc etc.

Hop count is as easy as it sounds: 1 per hop.

Router1 sends a RIP packet to Router 3. Below is the hop count values in the RIP-packet.

Router1

---

Router2

---

Router3

Count: 0

---

Count: 1

---

Count: 2

The hope count will be calculated as once the packet took an inbound & outbound in a router then it will considered as a hop.

That is if you the packet need to reach from RouterA to RouterC then

RotuerA

---

>RouterB

---

>routerC

here the packet RouterA is travilling through the inbound of RouterB as well as outbounded from RouterB and then it reaching its destination RouterC. Hence the packet took only one complete Inbound & outbound in only one router (RouterB) so this network having only one hop count.

Will take one more example.

RotuerA

---

>RouterB

---

>routerC

---

>RouterD

here will take that the packet needs to reach RouterD. Then the packet will pass two router's (in & out bound interfaces) to reach the destination. Hence this network having the hop count 2.


Hope it will clear your doubt.

nnbnbRotuerA

---

>RouterB

---

>routerC

---

>RouterD

Would be a hop count of 3

When a router receives a routing update that contains a new or changed destination network entry, the router adds 1 to the metric value indicated in the update and enters the network in the routing table.

www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/rip.htm

clear as the water, and dont try to be repetitive tive tive tive...
but if it is still not clear, in the last diagram you must understand!

RotuerA

---

link1---->RouterB

---

>routerC

---

>RouterD

link1 or subnet1 between router A and router B has a hop count of 2 from the Router D point of view or routing table.