Virtual router redudancy protocol questions

[sarahr202]

HI every body!

I have few questions:

1)In HSRP, one router is chosen as active while the other is chosen as standby, all the rest would be in listening state. What about VRRP?

In vrrp, one router is chosen as master,are all the rest chosen as back up routers? or only one router among them is chosen as backup router?

2)In HSRP, active router overwrite the timers configured on other routers in the group. How about in VRRP? does master in vrrp overwrite the timers on other routers in the group?

3) which routers can receive and send hello in VRRP and which ones can only listen ?

4) Do routers use hold time in VRRP?

thanks a lot!

[franktuck]

Hi Sarah,

I have attached a drawing of the network.

The router (red) and the one below will be connected to a patch panel. I'm not sure if that connection will be on the same pins.

If they are connected to the same pins will this affect the rip updates between the R1 & R2? (R2 is standby)

[sarahr202]

i will get back to you when i am done

[sarahr202]

Hi Frank!

you said router 2 is standby which it can not be.

The router R2 has serial interfaces in the network. Hrsp protocol is meant for ethernet interface or port. In fact if you try to configure hrsp under serial interface, you will get the message" unrecognised command"

From your diagram, it is obvious you are trying to provide gateway redundancy using hsrp, on 10.1.30/24 subnet which is connected to fe0/0 of Red router and fe/0 of router r1.

"The router (red) and the one below will be connected to a patch panel. I'm not sure if that connection will be on the same pins."

Here i assume " by same pins" you mean red router and the one below(r1) will be connected to same subnet(10.10.25.0/24). Even if they are not on the same pins( i.e different subnet) , it won't effect the rip updates.

However make sure you advertise the subnet 10.1.30.x/24 in rip or you will have reachability issue.

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But you have problem in hsrp setup.

First of all r2 can not be a standby hsrp router for the reason mentioned above.

2nd thing, only red router is hsrp gateway for the host on the subnet 10.1.30.0/24.

You don't have redundancy for gateway.If your red router goes down, the host on 10.1.30.0/24 will be cut off from rest of network.

In order to provide gateway redundancy and to make the most of HSRP, you should configure r1 as standby not r2.

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You could manipulate hsrp on these routers, red and r1 so that both links will be used at a time by hosts on 10.1.30.0/24 subnet.

If you need more help how to do it, just ask

Thanks a lot!

[franktuck]

Hi Sarah,

I hope I didn't add any confusion with the diagram. If you remove all the items in red that would be my current configuration. The 10.10.25.201 (P3) device is connected to the fe0/1 of the black router.

The red items depicts the proposed configuration.

Going forward both routers will have their s0 interface (10.10.65/24)connection to the same demarcation point.

HSRP will only be configured on the fe/0(10.1.30./24) of each router and each router track their own s0 interface.

Q: Will both routers receive the rip updates & user data?

Q: Can the 2811 support more that on default gateway?

[sarahr202]

i will get back to you in few hours Frank.

[franktuck]

awaiting your response.

[sarahr202]

Hi Frank!

"Going forward both routers will have their s0 interface (10.10.65/24)connection to the same demarcation point"

I will call red router as rR.

Now rR and R1 are connected by serial interface s0(10 .10.65.24).

How would these two routers r1 and rR be connected to r3?

Remember, you can connect single router on serial interface (if your are not using sub interface).

"HSRP will only be configured on the fe/0(10.1.30./24) of each router and each router track their own s0 interface."

Yes it will be fine , hosts on 10.1.30.0/24 can benefit from hsrp now. hsrp will not effect your rip updates and they both will receive user data as well if your are using two hsrp group , for one group say hsrp 1, r1 is active while rR is standby, for other group say hsrp 2 rR is actice while r1 is standby.

But will these two r1 and rR be able to forward ip packets from the hosts or receive the ip packets destined to host on 10.1.30.0/24?

The answer is if you connect these r1 and rR to properly to r3,and make sure you advertise the 10.1.30.0/24 subnet in rip so others routers will know about 10.1.30.0/24 subnet and thus be able to forward the packets destined to 10.1.30.0/24.

Q: Can the 2811 support more that on default gateway?

Yes,

If you need more help, just ask

[franktuck]

Hi Sarah,

How would these two routers r1 and rR be connected to r3?

The routers rR & R1 will be connected to r3 via the channelbanks (microwave link)

Will I have to use two hsrp groups or was this just an example use in your response?

Thanks.

[sarahr202]

yes you have to use two hsrp group so both routers r1 and Rr will load balance the traffic and as standby router for each other.

But you can not connect r1 and Rr and r3 using micro wave link by serial ports unless you are using sub interface which you are not.

without sun interface, router expects only router on the serial link.

Thanks a lot!