R4#sh ip ospf data external 5.5.5.5
OSPF Router with ID (4.4.4.4) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 767
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 5.5.5.5 (External Network Number )
Advertising Router: 1.1.1.1
LS Seq Number: 80000002
Checksum: 0xE0A6
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
Routing Bit Set on this LSA
LS age: 340
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 5.5.5.5 (External Network Number )
Advertising Router: 6.6.6.6
LS Seq Number: 80000002
Checksum: 0x2601
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 3.3.65.5
External Route Tag: 0
traceroute 5.5.5.5 nu
1 3.3.24.2 88 msec
3.3.34.3 68 msec
3.3.24.2 28 msec
2 3.3.36.6 68 msec
3.3.12.1 92 msec
3.3.36.6 64 msec
The result is that OSPF is not using the FA address in this case even it is set
this is what i meant :)
R1 and R6 are ASBR
________________________________
From: Marko Milivojevic [[email protected]]
Sent: Wednesday, June 19, 2013 7:09 PM
To: Elie Raad
Cc: Saleh Batouq; OSL Routing and Switching
Subject: Re: [OSL | CCIE_RS] OSPF Q
Well, you are mixing in two things here :-). The thread was originally about
the non-NSSA area. That's what I was answering about.
In a case of the NSSA area, behavior is slightly different. NSSA ASBR will set
FA as the IP field to one of its own IP addresses advertised in OSPF
(preference given to Loopback). When the translating ABR creates Type 5 LSA,
this information will be preserved, allowing fo the optimal routing to the ASBR.
--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor / Managing Partner - IPexpert
On Tue, Jun 18, 2013 at 10:55 PM, Elie Raad
<[email protected]<mailto:[email protected]>> wrote:
I mean in scenario where we have 2 Exits to O E1/E2 routes , OSPF will choose
to Replace the Advertising Router Attribute to the highest Router-id Value
between Both . in that case OSPF will route toward the one that is matched
inside the Advertising router value, this can cause sometimes sub-optimal
routing issue.
If the Forwarding Address value is set than OSPF will route toward the Fa
address field regardless of the one who did the T 7/5 Translation ensuring
Optimal path selection.
what if this same route has been advertised but now with the Advertising router
field set and the Fa field Set. and there is no Type 7/5 Translation since we
Satisfied the below conditions for setting the FA to non-zero. the question is
what will OSPF choose as a next hope to get this route installated in the RIB?
Regards,
Elie Raad | Network and Systems Administrator
American University of Science and Technology
[email protected]<mailto:[email protected]> | Office: +961-1-218716 Ext: 396
Office Hours: Mon- Fri 9:00 am-16:00 pm UTC+02:00
________________________________
From: Marko Milivojevic [[email protected]<mailto:[email protected]>]
Sent: Tuesday, June 18, 2013 11:27 PM
To: Elie Raad
Cc: Saleh Batouq; OSL Routing and Switching
Subject: Re: [OSL | CCIE_RS] OSPF Q
What would OSPF use as next-hop where?
--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor / Managing Partner - IPexpert
On Tue, Jun 18, 2013 at 11:09 AM, Elie Raad
<[email protected]<mailto:[email protected]>> wrote:
What will ospf use as a next hop , the advertising router ip address or the fa
address
Ignore any typos, sent from mobile device.
On Jun 18, 2013, at 19:17, "Marko Milivojevic"
<[email protected]<mailto:[email protected]>> wrote:
Yes it is :-)
On an ASBR that redistributes the route:
1) next-hop must be known by OSPF (enabled on the interface, or a more specific
OSPF route to it)
2) exit interface for the next-hop must not be passive
3) exit interface must be broadcast or non-broadcast
If those are satisfied, redistributed route will have non-zero FA and FA will
be the next-hop of the redistributed route.
--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor / Managing Partner - IPexpert
On Mon, Jun 17, 2013 at 11:13 PM, Saleh Batouq
<[email protected]<mailto:[email protected]>> wrote:
I would also like to know!!!
Best Regards,
Saleh
On Tue, Jun 18, 2013 at 9:22 AM, Elie Raad
<[email protected]<mailto:[email protected]>> wrote:
> Hi Guys ,
>
> is it possible to set the FA Address to non-zero for an O E1/E2 route?
>
>
>
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_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit
www.ipexpert.com<http://www.ipexpert.com>
Are you a CCNP or CCIE and looking for a job? Check out
www.PlatinumPlacement.com<http://www.PlatinumPlacement.com>
http://onlinestudylist.com/mailman/listinfo/ccie_rs
_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit
www.ipexpert.com
Are you a CCNP or CCIE and looking for a job? Check out
www.PlatinumPlacement.com
http://onlinestudylist.com/mailman/listinfo/ccie_rs
