Switching

Hi,

here is the configuration

ge0/0/1---vlan20  in switch1

ge0/0/2 --vlan20 in switch 2

switch1-ge0/0/2------ge0/0/2-switch2

protocol ospf area 0 interface vlan.20 in each switch

it seems neither of them send hello actively

http://forums.juniper.net/t5/Routing/Please-include-configurations-and-topologies-when-you-re-having/m-p/81312#U81312

This will help a lot in helping us to help you

configuration:

EX1:
show configuration interfaces ge-0/0/1
unit 0 {
    family ethernet-switching {
        vlan {
            members test;
        }
    }
}

 show configuration vlans                   
test {
    vlan-id 20;
    l3-interface vlan.20;
}


show configuration interfaces vlan.20
family inet {
    address 1.1.1.1/30;
}

show configuration protocols ospf   

area 0.0.0.1 {
    interface vlan.20;
}




EX2:
show configuration interfaces ge-0/0/2
unit 0 {
    family ethernet-switching {
        vlan {
            members test;
        }
    }
}

 show configuration vlans                   
test {
    vlan-id 20;
    l3-interface vlan.20;
}


show configuration interfaces vlan.20
family inet {
    address 1.1.1.2/30;
}

area 0.0.0.1 {
    interface vlan.20;
}

Can you check what is the state of adjacency between the routers.

show ospf neighbor

Hi,sorry to confuse

yes,it can be up in this case

actually my question is :if there are 4 interface in this vlan 20,would hello packet be sent out from all these 4 interfaces since all of them are in this vlan 20?

OSPF hello will be only sent through one of the interfaces generally the first interface. If the interface through which hellos are getting communicated goes down then the other interface will start sending the hellos.

No. OSPF packets are only sent out the interfaces that are configured in under the protocol ospf without the passive option.

>show ospf interfaces

suppose there are 4 interface in this vlan 20

area 0.0.0.1 {
    interface vlan.20;

}

4 of these interfaces will start send hellos ?or only one?

confused

If you have 4 interfaces configured for a vlan (sat vlan 10) and you are configuring vlan interface in the ospf

set protocols ospf area 0.0.0.0 interface vlan.10

then each interface won't send the hellos. My observation is that only the first interface in the vlan 10 will send the hellos.

ok,but other 3 interfaces can respond to hello packets from outside and bulid neighbor ,right?

Can you explain how you are configuring

4 interfaces in vlan 20

show protocols ospf  
area 0.0.0.1 {
    interface vlan.20;
}

there are 4 devices connected to these interfaces.

All I want to know is whether other 3 interface send hello packet on its own initative

If you configure like this --

R0 ----ge-0/0/1-------ge-0/0/1--R1----ge-0/0/2---------ge-0/0/2--R2

    -------ge-0/0/3-------ge-0/0/3

      ------ge-0/0/4 ------ge-0/0/4

All interfaces in vlan 10 . All routers are configured with ospf area0 with interface as vlan name . 

In this case R1 has 4 interfaces in vlan 10 and it will have send hello through ge-0/01 and ge-0/02

well,................

1:but u said only the first interface will send hello ,why ge-0/0/2 will send ?

2:if it is diagram ,what will happen?

all interface are in vlan 20 and vlan.20 is set under protocol ospf

R0 ----ge-0/0/1-------ge-0/0/1--R1

     ------ge-0/0/2------ge-0/0/2

    -------ge-0/0/3-------ge-0/0/3

      ------ge-0/0/4 ------ge-0/0/4

In above case only ge-0/0/1 will send hello

I have not tried your config but i suppose that all the interface should be sending hellos.

Hello Robbie,

I think you are confusing two different things (very easy to do-I am not saying that I was confused also 🙂

But vlan 20 is just the vlan identification value. vlan.20 is an interface all be it an internal logical Layer 3 interface, just like ge-0/0/1 or fe-0/0/2, at-x.x.x, gr-x.x.x etc. Soif you have multiple interfaces in the vlan 20, you would need to add each of the interfaces in the vlan for them to begin sending and responding to OSPF hello packets. Adding vlan.x does not add all the interfaces in vlan X, that is a single L3 routign interface.

https://www.juniper.net/techpubs/en_US/junos12.1/topics/example/ospf-single-area-configuring.html

>>>

To enable OSPF, you must configure one or more interfaces on the device within an OSPF area. Once the interfaces are configured, OSPF LSAs are transmitted on all OSPF-enabled interfaces, and the network topology is shared throughout the network.

did you run the command

>show ospf interface

How many interfaces did it show you that is running ospf?

here are some documents that that will help you understand OSPF

https://www.juniper.net/techpubs/en_US/junos12.1/information-products/pathway-pages/config-guide-routing/config-guide-ospf.html#overview

Hello

thanks very much

show ospf interface:

only vlan.20 is enabled

4 layer 2 interfaces  belongs to vlan 20

if I enable vlan.20 in protocol ospf,these 4 interfaces should send hello packets

I know vlan.20 is l3 interface,that is why I put it under protocol ospf

my question is :

since 4 interfaces belong to vlan 20.if I set protocol area 0 interface vlan.20,whether all of these 4 interface send hellos packet

hello should be sent out via these 4 "real" interface

Not sure where you are getting that understanding from, but you could share the source. How will an interface not configured or that is not running OSPF send hello packets? If you want those other 4 interfaces to send and recieve hello packets, add them to ospf.

Hello packets are multicast as part of neighbor discovery so yes, they will go out any port configured for the RVI's vlan. Adding a L2 interface to ospf is neither necessary nor possible.

thx

yes,I know only l3 interface can be configured unher protocol ospf area 0 interface

so if  interface vlan.20  is configured under protocol ospf area 0 interface,all l2 ports belong to this vlan will sed hello packets,right?

---

@Robbie wrote:

 

so if  interface vlan.20  is configured under protocol ospf area 0 interface,all l2 ports belong to this vlan will sed hello packets,right?

---

Maybe just stick a laptop or a PC on each port and run Wireshark on it for 30-60 seconds and see if you see any Hellos.

I would think that would clear it up.

---

Hi Some one help on this topology,

I have 2 internet connections and i would like to keep ISP 1 as primary for LAN users and ISP2 as backup for Lan users and i would like to keep automatic failover as well .and iam running OSPF between Cisco and Juniper devices.Can some one provide the configuration for the above topology with out any loop?...How can i export default route with diffrent priority through ospf...Can some one help on this?Please see the attached topology..