Re: BGP to OSPF Redistribution w/ Sham-Link

It's not stupid, just something not very often warned about in the
books and the documentation. Here's an exercise for you:

Now try the same thing by redistributing the Loopback into BGP instead
of using the network statement and see if it changes... ;-)

--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior Technical Instructor - IPexpert
On Wed, Oct 12, 2011 at 03:50, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
> I'm sure doing something relly stupid then :)
> I've just done it again, below the files to reproduce it.
> Just two PEs, serial link and a vrf. I configure it and SL (sham link)
> comes up fine. Bounce it and it does not.
> This config has some deviations from the standard template, like
> area 146 being an NSSA and BGP not being established from loopbacks,
> but that should not make a difference, I guess.
>
> -Carlos
>
> Sham.net:
> # Demo sham link
> [172.30.0.2]
>
> B  B [[7200]]
> B  B image = \var\c7200\ios\c7200-advipservicesk9-mz.124-15.T1.bin
> B  B npe = npe-400
> B  B ram = 160
>
> B  B [[ROUTER PE-Piz]]
> B  B console = 2001
> B  B s1/0 = F1 1
>
> B  B [[ROUTER PE-Lav]]
> B  B console = 2002
> B  B s1/0 = F1 2
>
> B  B [[ROUTER CE-Piz]]
> B  B console = 2003
> B  B f0/0 = PE-Piz f0/0
>
> B  B [[ROUTER CE-Lav]]
> B  B console = 2004
> B  B f0/0 = PE-Lav f0/0
>
> B  B [[FRSW F1]]
> B  B 1:102 = 2:201
> B  B 2:201 = 1:102
>
> -----
> PE-Lav:
> hostname PE-Lav
> !
> ip vrf M
> B rd 100:100
> B route-target export 100:100
> B route-target import 100:100
> !
> interface Loopback100
> B ip vrf forwarding M
> B ip address 10.68.146.228 255.255.255.255
> !
> interface FastEthernet0/0
> B ip vrf forwarding M
> B ip address 10.68.146.6 255.255.255.252
> !
> interface Serial1/0
> B no ip address
> B encapsulation frame-relay
> B serial restart-delay 0
> !
> interface Serial1/0.201 point-to-point
> B ip address 172.16.12.2 255.255.255.252
> B mpls ip
> B frame-relay interface-dlci 201
> !
> router ospf 400 vrf M
> B log-adjacency-changes
> B area 146 nssa
> B area 146 sham-link 10.68.146.228 10.68.146.227 cost 1000
> B network 10.68.146.4 0.0.0.3 area 146
> !
> router bgp 100
> B no synchronization
> B bgp log-neighbor-changes
> B neighbor 172.16.12.1 remote-as 100
> B no auto-summary
> B !
> B address-family vpnv4
> B neighbor 172.16.12.1 activate
> B neighbor 172.16.12.1 send-community extended
> B exit-address-family
> B !
> B address-family ipv4 vrf M
> B no synchronization
> B network 10.68.146.228 mask 255.255.255.255
> B exit-address-family
>
> ------
> PE-Piz:
> hostname PE-Piz
> !
> ip vrf M
> B rd 100:100
> B route-target export 100:100
> B route-target import 100:100
> !
> interface Loopback100
> B ip vrf forwarding M
> B ip address 10.68.146.227 255.255.255.255
> !
> interface FastEthernet0/0
> B ip vrf forwarding M
> B ip address 10.68.146.2 255.255.255.252
> !
> interface Serial1/0
> B no ip address
> B encapsulation frame-relay
> B serial restart-delay 0
> !
> interface Serial1/0.102 point-to-point
> B ip address 172.16.12.1 255.255.255.252
> B mpls ip
> B frame-relay interface-dlci 102
> !
> router ospf 400 vrf M
> B log-adjacency-changes
> B area 146 nssa
> B area 146 sham-link 10.68.146.227 10.68.146.228 cost 1000
> B network 10.68.146.0 0.0.0.3 area 146
> !
> router bgp 100
> B no synchronization
> B bgp log-neighbor-changes
> B neighbor 172.16.12.2 remote-as 100
> B no auto-summary
> B !
> B address-family vpnv4
> B neighbor 172.16.12.2 activate
> B neighbor 172.16.12.2 send-community extended
> B exit-address-family
> B !
> B address-family ipv4 vrf M
> B no synchronization
> B network 10.68.146.227 mask 255.255.255.255
> B exit-address-family
>
> ------
>
> Narbik Kocharians @ 12/10/2011 02:17 -0300 dixit:
>>
>> *There's nothing really difficult with sham-links, if you follow the
>> steps for configuration.
>> *
>> I agree 1000 percent.
>>
>>
>>
>> On Tue, Oct 11, 2011 at 5:42 PM, Marko Milivojevic
>> <markom_at_ipexpert.com>wrote:
>>
>>> On Tue, Oct 11, 2011 at 16:22, Carlos G Mendioroz <tron_at_huapi.ba.ar>
>>> wrote:
>>>>
>>>> I said that I've just seen a test case where the link does not come
>>>> up, even with the loopback published in BGP and not in OSPF.
>>>> So I don't fit in your rule.
>>>
>>> ... if you have redistribution from BGP to OSPF, then you are very
>>> much advertising loopbacks in OSPF, unless you were filtering. If you
>>> were filtering, then you probably had an entirely different MPLS
>>> transport issue, which only manifested itself by sham-links not coming
>>> up.
>>>
>>> There's nothing really difficult with sham-links, if you follow the
>>> steps for configuration.
>>>
>>> --
>>> Marko Milivojevic - CCIE #18427 (SP R&S)
>>> Senior Technical Instructor - IPexpert
>>>
>>>
>>> B Blogs and organic groups at http://www.ccie.net
>>>
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>>
>>
>
> --
> Carlos G Mendioroz B <tron_at_huapi.ba.ar> B LW7 EQI B Argentina
Blogs and organic groups at http://www.ccie.net