[j-nsp] OSPF Sham link question
Daniel Lete
daniel.lete at heanet.ie
Fri Dec 7 05:13:59 EST 2007
Hello Sergio,
In the PE where the CE is connected to, LSA Type-1 from CE should be seen as
LSA Type-1
In the remote PE, LSA Type-1 from that same CE should be seen as LSA Type-3
(inter-area)
Daniel
Sergio D. wrote:
> But you should at least be learning the loopbacks from each side as a
> type-1 LSA.
> How are these routes showing on the PEs "show route protocol ospf table
> sham-link-test" ? I think I missed that output or sorry if it was already
> mentioned.
>
>
>
> Message: 4
> Date: Thu, 06 Dec 2007 15:04:03 +0000
> From: Daniel Lete <daniel.lete at heanet.ie>
> Subject: Re: [j-nsp] OSPF Sham link question
> To: David Ball <davidtball at gmail.com>
> Cc: juniper-nsp at puck.nether.net
> Message-ID: <47580F63.10905 at heanet.ie>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hello David,
> Your comment below:
> > (NB: is it normal that the routes PE2 is learning from the m10 are
> 'Extern' ?)
>
> may not be related at all with sham links or even with rfc2547/rfc4364. If
> you
> are injecting prefixes into OSPF (redistribute in Cisco or export in
> Juniper)
> in your CE, then those prefixes will appear as LSA Type-5 (external if you
> want).
>
> Daniel
>
>
>
> David Ball wrote:
>> Should have mentioned earlier (in case it's relevant), the reason
>> for sham-link requirement is that there 'will' be a slow backup link
>> between the cisco and the m10, but it'll be direct, so the cisco and
>> m10 will think that's the better link (due to intra-area). So, was
>> hoping to use sham-link across T640s to bring things closer to 'par'
>> and have those routes appear as intra-area and ultimately prefer the
>> sham-link.
>> I was, but am no longer, explicitly exporting routes from BGP into
>> OSPF on the PEs. As requested, more configs and show cmd output
>> included. I appreciate the feedback so far by the way....thanks
>> again.
>>
>> m10's loopback is 172.16.0.3
>> cisco's loopback is 172.16.0.4
>>
>> Pertinent configs from PE1 (T640 facing Cisco):
>> lo0 {
>> unit 800 {
>> description "sham-link testing";
>> family inet {
>> filter {
>> input secure-router-shamlink-test;
>> }
>> address 172.16.0.2/32;
>> }
>> }
>> }
>>
>> ge-7/0/0 { <---- int facing Cisco
>> unit 0 {
>> family inet {
>> address 172.16.2.1/30;
>> }
>> }
>> }
>>
>> sham-link-test {
>> instance-type vrf;
>> interface ge-7/0/0.0;
>> interface lo0.800;
>> vrf-target target:25983:800;
>> vrf-table-label;
>> protocols {
>> ospf {
>> sham-link local 172.16.0.2;
>> area 0.0.0.0 {
>> sham-link-remote 172.16.0.1 metric 1;
>> interface ge-7/0/0.0 {
>> metric 1;
>> }
>> }
>> }
>> }
>> }
>>
>>
>> Pertinent configs from PE2 (T640 facing M10):
>>
>> lo0 {
>> unit 800 {
>> description "sham-link test";
>> family inet {
>> filter {
>> input secure-router-shamlink-test;
>> }
>> address 172.16.0.1/32;
>> }
>> }
>> }
>>
>> ge-7/2/1 { <--------facing m10
>> unit 0 {
>> family inet {
>> address 172.16.1.1/30;
>> }
>> }
>> }
>>
>> sham-link-test {
>> instance-type vrf;
>> interface ge-7/2/1.0;
>> interface lo0.800;
>> vrf-target target:25983:800;
>> vrf-table-label;
>> protocols {
>> ospf {
>> sham-link local 172.16.0.1;
>> area 0.0.0.0 {
>> sham-link-remote 172.16.0.2 metric 1;
>> interface ge-7/2/1.0 {
>> metric 1;
>> }
>> }
>> }
>> }
>> }
>>
>> OSPF neighbors as seen from PE1:
>>> show ospf neighbor instance sham-link-test
>> Address Interface State ID Pri
> Dead
>> 172.16.2.2 ge-7/0/0.0 Full 172.16.0.4 1
> 36
>> OSPF neighbors as seen from PE2:
>>> show ospf neighbor instance sham-link-test
>> Address Interface State ID Pri
> Dead
>> 172.16.1.2 ge-7/2/1.0 Full 172.16.0.3 128
> 31
>> Proof that PE1 is learning PE2's loopback via BGP:
>>> show route table sham-link-test
>> sham-link-test.inet.0: 9 destinations, 9 routes (9 active, 0 holddown, 0
> hidden)
>> + = Active Route, - = Last Active, * = Both
>>
>> 172.16.0.1/32 *[BGP/170] 12:43:03, localpref 100, from 1.7.1.43
>> AS path: I
>> > to 1.7.2.18 via ge-0/2/0.0, label-switched-path
>> NCP-LSP-00819-005-043
>> to 1.7.2.1 via ge-0/0/0.0, label-switched-path
>> NCP-LSP-00819-005-043
>> 172.16.0.2/32 *[Direct/0] 20:29:55
>> > via lo0.800
>>
>> Proof that PE2 is learning PE1's loopback via BGP:
>>> show route table sham-link-test
>> sham-link-test.inet.0: 9 destinations, 9 routes (9 active, 0 holddown, 0
> hidden)
>> + = Active Route, - = Last Active, * = Both
>>
>> 172.16.0.1/32 *[Direct/0] 21:04:41
>> > via lo0.800
>> 172.16.0.2/32 *[BGP/170] 18:50:17, localpref 100, from 1.7.1.5
>> AS path: I
>> > to 1.7.2.17 via ge-0/2/0.0, label-switched-path
>> NCP-LSP-00829-043-005
>> to 1.7.2.5 via ge-0/0/0.0, label-switched-path
>> NCP-LSP-00829-043-005
>>
>> OSPF database according to PE1 (Cisco isn't sending much/anything...my
>> current goal is for the Cisco to learn what the m10 sends, then I'll
>> move on):
>>> show ospf database instance sham-link-test
>> OSPF link state database, Area 0.0.0.0
>> Type ID Adv Rtr Seq Age Opt Cksum
> Len
>> Router *172.16.0.2 172.16.0.2 0x80000037 876 0x22 0xfdff
> 36
>> Router 172.16.0.4 172.16.0.4 0x80000029 1111 0x22 0xa757
> 36
>> Network 172.16.2.2 172.16.0.4 0x80000022 1372 0x22 0x9a80
> 32
>>
>> OSPF database according to PE2:
>>> show ospf database instance sham-link-test
>> OSPF link state database, Area 0.0.0.0
>> Type ID Adv Rtr Seq Age Opt Cksum
> Len
>> Router *172.16.0.1 172.16.0.1 0x80000024 1912 0x22 0x1ef6
> 36
>> Router 172.16.0.3 172.16.0.3 0x80000425 735 0x22 0xc475
> 48
>> Network 172.16.1.2 172.16.0.3 0x8000002e 435 0x22 0x7b97
> 32
>> OpaqArea 1.0.0.1 172.16.0.3 0x80000413 1335 0x22 0xaeea
> 28
>> OSPF AS SCOPE link state database
>> Type ID Adv Rtr Seq Age Opt Cksum
> Len
>> Extern 172.16.16.0 172.16.0.3 0x80000034 1035 0x22 0xbf33
> 36
>> Extern 192.168.101.0 172.16.0.3 0x80000036 135 0x22 0xe40a
> 36
>> (NB: is it normal that the routes PE2 is learning from the m10 are
> 'Extern' ?)
>> Here is Cisco's current routing table (learning nothing via OSPF):
>> lab-2651#sho ip route
>> Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
>> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
>> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
>> E1 - OSPF external type 1, E2 - OSPF external type 2
>> i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS
> level-2
>> ia - IS-IS inter area, * - candidate default, U - per-user static
> route
>> o - ODR, P - periodic downloaded static route
>>
>> Gateway of last resort is not set
>>
>> C 172.17.0.0/16 is directly connected, FastEthernet0/1
>> 172.16.0.0/30 is subnetted, 1 subnets
>> C 172.16.2.0 is directly connected, FastEthernet0/0
>> C 208.98.239.0/24 is directly connected, FastEthernet0/1
>> lab-2651#
>>
>>
>> Here is M10's inet.0 routing table:
>>> show route
>> inet.0: 10 destinations, 10 routes (10 active, 0 holddown, 0 hidden)
>> Restart Complete
>> + = Active Route, - = Last Active, * = Both
>>
>> 0.0.0.0/0 *[Static/5] 5w4d 23:37:59
>> Reject
>> 172.16.0.3/32 *[Direct/0] 2w0d 19:06:21
>> > via lo0.0
>> 172.16.1.0/30 *[Direct/0] 21:05:30
>> > via ge-0/1/0.0
>> 172.16.1.2/32 *[Local/0] 21:05:30
>> Local via ge-0/1/0.0
>> 172.16.16.0/24 *[Static/5] 21:02:54
>> Discard
>> 192.168.8.0/24 *[Static/5] 5w4d 23:37:59
>> > to 192.168.101.252 via fxp0.0
>> 192.168.9.0/24 *[Static/5] 5w4d 23:37:59
>> > to 192.168.101.252 via fxp0.0
>> 192.168.101.0/24 *[Direct/0] 5w4d 23:37:59
>> > via fxp0.0
>> 192.168.101.33/32 *[Local/0] 5w4d 23:37:59
>> Local via fxp0.0
>> 224.0.0.5/32 *[OSPF/10] 5w4d 23:38:00, metric 1
>> MultiRecv
>>
>>
>>
>> On 05/12/2007, Peter E. Fry <pfry-lists at redsword.com> wrote:
>>> ----- Original Message -----
>>> From: Daniel Lete <daniel.lete at heanet.ie>
>>>
>>> [...]
>>>> In relation to your sham-link. You need a loopback IP
>>>> within your VRF to act as source/destination of the sham
>>>> link and these loopbacks are NOT to be announced to your
>>>> CE.
>>> I was going to make that point -- that is, I would not
>>> expect to see:
>>>
>>>> O IA 172.16.0.3/32 [110/11] via 172.16.2.1, 04:31:29,
>>> FastEthernet0/0
>>>
>>> ...(although I could be wrong -- I don't get many looks into
>>> CPE). Also, I'd expect the sham-link neighbor to show up on
>>> the PE. You can see them on Cisco PEs, for instance:
>>>
>>> CiscoPE#show ip ospf [process] neighbor
>>>
>>> Neighbor ID Pri State Dead Time Address
>>> Interface
>>> [...]
>>> [Remote ID IP] 0 FULL/ - - [Remote LB
>>> IP] OSPF_SLn
>>> [...]
>>> CiscoPE#
>>>
>>> ...so there's no confusion as to the state of the sham link.
>>> I don't have a Juniper L3 VPN PE or a Cisco CE handy.
>>>
>>> Peter E. Fry
>>>
>>>
>>>
>>> _______________________________________________
>>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>>>
>> _______________________________________________
>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>>
>
> --
> Daniel Lete Murugarren
> HEAnet Limited, Ireland's Education and Research Network
> 1st Floor, 5 George's Dock, IFSC, Dublin 1
> Registered in Ireland, no 275301 tel: +353-1-660 9040 fax: +353-1-660 3666
> web: http://www.heanet.ie/
>
>
--
Daniel Lete Murugarren
HEAnet Limited, Ireland's Education and Research Network
1st Floor, 5 George's Dock, IFSC, Dublin 1
Registered in Ireland, no 275301 tel: +353-1-660 9040 fax: +353-1-660 3666
web: http://www.heanet.ie/
More information about the juniper-nsp
mailing list