From: Chuck Larrieu (chuck@xxxxxxxxxxxxx)
Date: Wed Feb 28 2001 - 01:58:37 GMT-3
Slight correction to below. This is why OSPF / frame relay can be so
mindbending.
On a point to point link, yes, no issues. on a frame relay subinterface
configured as an int s0.1 point, for example sh ip ospf int will reveal an
ospf network type point-to-point
However, on a frame relay subinterface configured as a multipoint, OSPF
considers that a non broadcast network. As we all know, nothing happens.
Adjacencies don't form. Now the confusion begins. If you examine the sh ip
opsf int output, you will see reference to the election of a DR on a non
broadcast network. (Wait time before Designated router selection 00:01:52)
If you set up the appropriate neighbor statements, a designated router and
backup designated router will be elected. If you change the ospf network
type to point-to-multipoint, you still have the DR/BDR election occur. This
can be bad news in a hub and spoke situation where one of the spokes is the
DR.
If, however, you have a point-to-multipoint on the hub, and point-to-points
on the spokes, then for all intents and purposes, you have a series of
point-to-point networks and no DR/BDR issues. the only other trick in this
case is that the hello timer must be adjusted because the
point-to-multipoint timer is different than a point-to-point timer ( 30 vs
10 )
Fun, huh.
Chuck
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jorge Mastrapa
Sent: Tuesday, February 27, 2001 3:29 PM
To: Fabricio Aponte; ccielab@groupstudy.com
Subject: RE: IP OSPF neigh in INIT/DROTHER state
Fabricio et. all.
Ethernet is a broadcast environment, and since you did not posted your
configs.. Judging by the sh commands and your question you configured
network statements on the interfaces, that's the cause of your problems..
Take a look at my examples below.. I'm fried now, and not logged into my
routers ( commands by memory ) but, if you are configuring OSPF in a LAN
environment you only need..
When you configure Point-to-Point or Point-to-Multipoint you will have
adjacencies, but not DR or BDR.. ( Since the process thinks there are only
two routers on that link so, no need to have a central brain to distribute
LSA information..
The routers don't see each other because if you are going to configure
neighbors you must have a non broadcast network..
R1
int e 0
ip add 1.1.1.1 255.255.255.0
router ospf 10
network 1.1.1.0 0.0.0.255 area 0
R2
int e 0
ip add 1.1.1.2 255.255.255.0
router ospf 10
net 1.1.1.0 0.0.0.255 area 0
OK, you should use the Loopback for router ID but you DON'T have to..
NOW if you want to configure the ethernet network as non-broadcast that's
different.. Then the neighbor command will work..
R1
int e 0
ip add 1.1.1.1 255.255.255.0
ip ospf network non-broadcast
router ospf 10
network 1.1.1.0 0.0.0.255 area 0
neighbor 1.1.1.2
R2
int e 0
ip add 1.1.1.2 255.255.255.0
ip ospf network non-broadcast
router ospf 10
net 1.1.1.0 0.0.0.255 area 0
neighbor 1.1.1.1
Please see
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_c
/ipcprt2/1cdospf.htm#22084 for additional info..
my $.02
J.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
sanjay
Sent: Tuesday, February 27, 2001 5:56 PM
To: Steven Weber; Fabricio Aponte; ccielab@groupstudy.com
Subject: Re: IP OSPF neigh in INIT/DROTHER state
Yep..you right. I was thinking Frame Relay.
----- Original Message -----
From: "Steven Weber" <itweber@earthlink.net>
To: "Fabricio Aponte" <fabricio@ev1.net>; <ccielab@groupstudy.com>; "sanjay"
<ccienxtyear@hotmail.com>
Sent: Monday, February 26, 2001 5:00 PM
Subject: Re: IP OSPF neigh in INIT/DROTHER state
>
> ethernet is not a point-to-point network even if there are only 2 hosts on
> the network
>
>
> ----- Original Message -----
>
> From: sanjay
>
>
> To: ccielab@groupstudy.com ;Fabricio
> Aponte
>
> Sent: 2/26/01 8:01:02 PM
>
> Subject: Re: IP OSPF neigh in INIT/DROTHER
> state
>
>
>
>
>
> I think on a point-to-point network, you won't have a DR or a BDR.
>
>
>
> thanks,
>
>
>
> ----- Original Message -----
>
> From: "Fabricio Aponte" fabricio@ev1.net
>
> To: ccielab@groupstudy.com
>
> Sent: Monday, February 26, 2001 12:29 PM
>
> Subject: IP OSPF neigh in INIT/DROTHER state
>
>
>
>
>
> I got two routers connected to each other via an ethernet
> hub. R2 and R5.
>
> This is the show ip ospf neigh on r 2 and show ip ospf int e 0 on
> both
>
> routers. Both routers are electing each other as the DR and
> no BDR (they
>
> do
>
> not see each other).
>
>
>
> Why are these two guys not electing a DR?
>
> Why is R5 not even seeing R2 as a neighbor?
>
>
>
> r2#show ip ospf neigh
>
>
>
> Neighbor ID Pri
> State Dead
> Time Address
>
> Interface
>
> 172.168.91.1 1
> INIT/DROTHER 00:00:30 216.12.210.81
>
> Ethernet0
>
>
>
>
>
> r2#show ip ospf int e 0
>
> Ethernet0 is up, line protocol is up
>
> Internet Address 216.12.210.82/24, Area 0
>
> Process ID 99, Router ID 100.100.100.1, Network Type
> BROADCAST, Cost: 10
>
> Transmit Delay is 1 sec, State DR, Priority 1
>
> Designated Router (ID) 100.100.100.1, Interface address
> 216.12.210.82
>
> No backup designated router on this network
>
> Timer intervals configured, Hello 10, Dead 40, Wait 40,
> Retransmit 5
>
> Hello due in 00:00:04
>
> Index 1/1, flood queue length 0
>
> Next 0x0(0)/0x0(0)
>
> Last flood scan length is 0, maximum is 0
>
> Last flood scan time is 0 msec, maximum is 0 msec
>
> Neighbor Count is 1, Adjacent neighbor count is 0
>
> Suppress hello for 0 neighbor(s)
>
> r2#
>
> [Resuming connection 5 to r5 ... ]
>
>
>
> r5#show ip ospf int e 0
>
> Ethernet0 is up, line protocol is up
>
> Internet Address 216.12.210.81/24, Area 0
>
> Process ID 99, Router ID 172.168.91.1, Network Type
> BROADCAST, Cost: 10
>
> Transmit Delay is 1 sec, State DR, Priority 1
>
> Designated Router (ID) 172.168.91.1, Interface address
> 216.12.210.81
>
> No backup designated router on this network
>
> Timer intervals configured, Hello 10, Dead 40, Wait 40,
> Retransmit 5
>
> Hello due in 00:00:09
>
> Neighbor Count is 0, Adjacent neighbor count is 0
>
> Suppress hello for 0 neighbor(s)
>
>
>
> Thank you,
>
>
>
>
>
> fabricio
>
>
>
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