On 9/30/10 12:57 AM, Mark Smith wrote:
On Thu, 30 Sep 2010 14:13:11 +1000
Julien Goodwin [1]<nanog at studio442.com.au> wrote:
On 30/09/10 13:42, Mark Smith wrote:
One of the large delays you see in OSPF is election of the designated
router on multi-access links such as ethernets. As ethernet is being
very commonly used for point-to-point non-edge links, you can eliminate
that delay and also the corresponding network LSA by making OSPF treat
the link as a point-to-point link e.g.
int ethernet0
ip ospf network point-to-point
If your implementation doesn't support point-to-point mode for an
interface, point-to-multipoint mode on an ethernet would achieve
something somewhat equivalent.
Do any implementations go point-to-point automatically if an ethernet
has a /30 or /31 mask?
Don't know.
Nope. Not Cisco anyway.
NDC-R1-CustA(config)#int f0/0
NDC-R1-CustA(config-if)#ip addr 10.111.1.1 255.255.255.254
% Warning: use /31 mask on non point-to-point interface cautiously
NDC-R1-CustA(config-if)#
*Sep 30 15:18:22.710: %OSPF-5-ADJCHG: Process 1, Nbr 10.133.1.2 on
FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or
detached
NDC-R1-CustA(config-if)#
NDC-R1-CustA(config-if)#do sh ip o i f0/0 | i Type|Address
Internet Address 10.111.1.1/31, Area 0
Process ID 1, Router ID 192.168.1.1, Network Type BROADCAST, Cost: 1
NDC-R1-CustA(config-if)#
HTH,
Scott
On 9/30/10 12:57 AM, Mark Smith wrote:
On Thu, 30 Sep 2010 14:13:11 +1000
Julien Goodwin [2]<nanog at studio442.com.au> wrote:
On 30/09/10 13:42, Mark Smith wrote:
One of the large delays you see in OSPF is election of the designated
router on multi-access links such as ethernets. As ethernet is being
very commonly used for point-to-point non-edge links, you can eliminate
that delay and also the corresponding network LSA by making OSPF treat
the link as a point-to-point link e.g.
int ethernet0
ip ospf network point-to-point
If your implementation doesn't support point-to-point mode for an
interface, point-to-multipoint mode on an ethernet would achieve
something somewhat equivalent.
Do any implementations go point-to-point automatically if an ethernet
has a /30 or /31 mask?
Don't know.
If you want to see what interface model OSPF is using, on a Cisco you
use
show ip ospf interface <blah>
The interface type for loopback interfaces can be a bit surprising and
the consequences a bit unexpected if you're intentionally or
otherwise not using a /32 prefix length on one.
Regards,
Mark.
References
1. mailto:nanog at studio442.com.au
2. mailto:nanog at studio442.com.au