In external LSAa there's no option field that's why the external route tag is 
used instead -this value is set automatically on the PE router during 
redistribution from bgp to ospf and encodes the as# of the PE's bgp process
So we don't need to worry about the domain tag in single as environment

However domain tag needs to be considered when your vpn spans across multiple 
AS'es (or ISPS) and there's a back-door link that starts in one AS and emerges 
in other AS
That's where the domain tag needs to be adjusted manually so that all PE 
routers serving sites where the back-door link starts and site where it ends 
share the same value to prevent form routig-loops to occure

adam

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of 
[email protected]
Sent: Monday, March 15, 2010 10:25 PM
To: [email protected]
Subject: CCIE_SP Digest, Vol 36, Issue 9

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Today's Topics:

   1. Type-5 LSA from CE to PE----MPLS core (venkat)
   2. Re: Type-5 LSA from CE to PE----MPLS core (Marko Milivojevic)
   3. Re: Type-5 LSA from CE to PE----MPLS core (venkat)
   4. Down bit (venkat)


----------------------------------------------------------------------

Message: 1
Date: Tue, 16 Mar 2010 02:37:40 +0530
From: venkat <[email protected]>
Subject: [OSL | CCIE_SP] Type-5 LSA from CE to PE----MPLS core
To: "<[email protected]>" <[email protected]>
Message-ID:
        <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

Hi,

I am stuck with a problem. In the below topology;

CE1------PE1----- MPLS---- PE2----CE2

CE1 is sending OSPF type-5 external LSA (generated by a redistributing
specific loopback IP) and i could see this lsa in PE1's ospf database. But,
not in BGP vpnv4 table. Is this expected behavior? I though as the tag=0,by
default, E2 routes are not redistributed into BGP vpnv4. tried with changing
tag value to 100 and still no success.

Below is the configuration;

<snip from R0-CE1>

                Type-5 AS External Link States

Link ID         ADV Router      Age         Seq#       Checksum Tag
22.22.22.22     100.100.100.100 463         0x80000001 0x003B17 100

<From R1 - PE1>
OSPF 1 VRF

                Type-5 AS External Link States

Link ID         ADV Router      Age         Seq#       Checksum Tag
22.22.22.22     100.100.100.100 715         0x80000001 0x003B17 100
R2#
!
 address-family ipv4 vrf one
  redistribute ospf 2 vrf one
  no synchronization
 exit-address-family
R2#
R2#show ip bgp  vpnv4 vrf one  <*<< not seeing type-5 LSA*
BGP table version is 50, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf one)
*> 11.1.1.0/24      0.0.0.0                  0         32768 ?
*> 12.1.1.0/24      0.0.0.0                  0         32768 ?
*>i13.1.1.0/24      5.5.5.5                  0    100      0 ?
*>i13.1.2.0/24      5.5.5.5                  0    100      0 ?
*> 100.100.100.100/32
                    12.1.1.2                 2         32768 ?
*>i192.168.2.0      5.5.5.5                  2    100      0 ?
R2#

Thanks,
Venkat
http://ippoint.wordpress.com/
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------------------------------

Message: 2
Date: Mon, 15 Mar 2010 21:09:58 +0000
From: Marko Milivojevic <[email protected]>
Subject: Re: [OSL | CCIE_SP] Type-5 LSA from CE to PE----MPLS core
To: venkat <[email protected]>
Cc: "<[email protected]>" <[email protected]>
Message-ID:
        <[email protected]>
Content-Type: text/plain; charset=UTF-8

Try this in BGP config for VRF one:

redist ospf 2 vrf one match internal external

--
Marko Milivojevic - CCIE #18427
Senior Technical Instructor - IPexpert

Mailto: [email protected]
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
Web: http://www.ipexpert.com/

On Mon, Mar 15, 2010 at 21:07, venkat <[email protected]> wrote:
> Hi,
> I am stuck with a problem. In the below topology;
> CE1------PE1----- MPLS---- PE2----CE2
> CE1 is sending OSPF type-5 external LSA (generated by a redistributing
> specific loopback IP) and i could see this lsa in PE1's ospf database. But,
> not in BGP vpnv4 table. Is this expected behavior? I though as the tag=0,by
> default, E2 routes are not redistributed into BGP vpnv4.?tried?with changing
> tag value to 100 and still no success.
> Below is the configuration;
> <snip from R0-CE1>
> ?? ? ? ? ? ? ? ?Type-5 AS External Link States
> Link ID ? ? ? ? ADV Router ? ? ?Age ? ? ? ? Seq# ? ? ? Checksum Tag
> 22.22.22.22 ? ? 100.100.100.100 463 ? ? ? ? 0x80000001 0x003B17 100
> <From R1 - PE1>
> OSPF 1 VRF
> ?? ? ? ? ? ? ? ?Type-5 AS External Link States
> Link ID ? ? ? ? ADV Router ? ? ?Age ? ? ? ? Seq# ? ? ? Checksum Tag
> 22.22.22.22 ? ? 100.100.100.100 715 ? ? ? ? 0x80000001 0x003B17 100
> R2#
> !
> ?address-family ipv4 vrf one
> ??redistribute ospf 2 vrf one
> ??no synchronization
> ?exit-address-family
> R2#
> R2#show ip bgp ?vpnv4 vrf one ?<<< not seeing type-5 LSA
> BGP table version is 50, local router ID is 2.2.2.2
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
> ?? ? ? ? ? ? ?r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
> ?? Network ? ? ? ? ?Next Hop ? ? ? ? ? ?Metric LocPrf Weight Path
> Route Distinguisher: 1:1 (default for vrf one)
> *> 11.1.1.0/24 ? ? ?0.0.0.0 ? ? ? ? ? ? ? ? ?0 ? ? ? ? 32768 ?
> *> 12.1.1.0/24 ? ? ?0.0.0.0 ? ? ? ? ? ? ? ? ?0 ? ? ? ? 32768 ?
> *>i13.1.1.0/24 ? ? ?5.5.5.5 ? ? ? ? ? ? ? ? ?0 ? ?100 ? ? ?0 ?
> *>i13.1.2.0/24 ? ? ?5.5.5.5 ? ? ? ? ? ? ? ? ?0 ? ?100 ? ? ?0 ?
> *> 100.100.100.100/32
> ?? ? ? ? ? ? ? ? ? ?12.1.1.2 ? ? ? ? ? ? ? ? 2 ? ? ? ? 32768 ?
> *>i192.168.2.0 ? ? ?5.5.5.5 ? ? ? ? ? ? ? ? ?2 ? ?100 ? ? ?0 ?
> R2#
> Thanks,
> Venkat
> http://ippoint.wordpress.com/
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
>


------------------------------

Message: 3
Date: Tue, 16 Mar 2010 02:46:08 +0530
From: venkat <[email protected]>
Subject: Re: [OSL | CCIE_SP] Type-5 LSA from CE to PE----MPLS core
To: Marko Milivojevic <[email protected]>
Cc: "<[email protected]>" <[email protected]>
Message-ID:
        <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

ha. My Bad... Thanks Marko.. Forgot that only inter and intra area ospf
routes are redistributed by default.. :)
Now everything looks good.

Regards,
venkat

On Tue, Mar 16, 2010 at 2:39 AM, Marko Milivojevic <[email protected]>wrote:

> Try this in BGP config for VRF one:
>
> redist ospf 2 vrf one match internal external
>
> --
> Marko Milivojevic - CCIE #18427
> Senior Technical Instructor - IPexpert
>
> Mailto: [email protected]
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> Web: http://www.ipexpert.com/
>
> On Mon, Mar 15, 2010 at 21:07, venkat <[email protected]> wrote:
> > Hi,
> > I am stuck with a problem. In the below topology;
> > CE1------PE1----- MPLS---- PE2----CE2
> > CE1 is sending OSPF type-5 external LSA (generated by a redistributing
> > specific loopback IP) and i could see this lsa in PE1's ospf database.
> But,
> > not in BGP vpnv4 table. Is this expected behavior? I though as the
> tag=0,by
> > default, E2 routes are not redistributed into BGP vpnv4. tried with
> changing
> > tag value to 100 and still no success.
> > Below is the configuration;
> > <snip from R0-CE1>
> >                 Type-5 AS External Link States
> > Link ID         ADV Router      Age         Seq#       Checksum Tag
> > 22.22.22.22     100.100.100.100 463         0x80000001 0x003B17 100
> > <From R1 - PE1>
> > OSPF 1 VRF
> >                 Type-5 AS External Link States
> > Link ID         ADV Router      Age         Seq#       Checksum Tag
> > 22.22.22.22     100.100.100.100 715         0x80000001 0x003B17 100
> > R2#
> > !
> >  address-family ipv4 vrf one
> >   redistribute ospf 2 vrf one
> >   no synchronization
> >  exit-address-family
> > R2#
> > R2#show ip bgp  vpnv4 vrf one  <<< not seeing type-5 LSA
> > BGP table version is 50, local router ID is 2.2.2.2
> > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > internal,
> >               r RIB-failure, S Stale
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >    Network          Next Hop            Metric LocPrf Weight Path
> > Route Distinguisher: 1:1 (default for vrf one)
> > *> 11.1.1.0/24      0.0.0.0                  0         32768 ?
> > *> 12.1.1.0/24      0.0.0.0                  0         32768 ?
> > *>i13.1.1.0/24      5.5.5.5                  0    100      0 ?
> > *>i13.1.2.0/24      5.5.5.5                  0    100      0 ?
> > *> 100.100.100.100/32
> >                     12.1.1.2                 2         32768 ?
> > *>i192.168.2.0      5.5.5.5                  2    100      0 ?
> > R2#
> > Thanks,
> > Venkat
> > http://ippoint.wordpress.com/
> >
> > _______________________________________________
> > For more information regarding industry leading CCIE Lab training, please
> > visit www.ipexpert.com
> >
> >
>
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------------------------------

Message: 4
Date: Tue, 16 Mar 2010 02:54:59 +0530
From: venkat <[email protected]>
Subject: [OSL | CCIE_SP] Down bit
To: Marko Milivojevic <[email protected]>
Cc: "<[email protected]>" <[email protected]>
Message-ID:
        <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

Yet another question. I am aware the down bit is set when the summary routes
(type-3 lsa) are redistributed from PE to CE so that other PE routers will
ignore the LSA. But it is not set in Type-5 LSA (not tested with type-7)..

Though, http://tools.ietf.org/html/rfc4576 says
"When the PE receives, from a CE router, a type 3, 5, or 7 LSA with the DN
bit set, the information from that LSA MUST NOT be used during

the OSPF route calculation.  As a result, the LSA is not translated
into a BGP route.  The DN bit MUST be ignored in all other LSA types"


Is there any reason why we are not using/set "DN" bit for type-5/7 as well
and using "domain tag" instead?

R6#show ip ospf database summary 100.100.100.100

            OSPF Router with ID (6.6.6.6) (Process ID 1)

                Summary Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 39
  Options: (No TOS-capability, DC, Downward)
  LS Type: Summary Links(Network)
  Link State ID: 100.100.100.100 (summary Network Number)
  Advertising Router: 13.1.2.1
  LS Seq Number: 80000001
  Checksum: 0x7A9D
  Length: 28
  Network Mask: /32
        TOS: 0  Metric: 2


R6#show ip ospf database external 22.22.22.22

            OSPF Router with ID (6.6.6.6) (Process ID 1)

                Type-5 AS External Link States

  Routing Bit Set on this LSA
  LS age: 44
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: 22.22.22.22 (External Network Number )
  Advertising Router: 13.1.2.1
  LS Seq Number: 80000002
  Checksum: 0xAAB9
  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: 3489660929

R6#

Thanks,
Venkat

On Tue, Mar 16, 2010 at 2:46 AM, venkat <[email protected]> wrote:

> ha. My Bad... Thanks Marko.. Forgot that only inter and intra area ospf
> routes are redistributed by default.. :)
> Now everything looks good.
>
> Regards,
> venkat
>
>
> On Tue, Mar 16, 2010 at 2:39 AM, Marko Milivojevic <[email protected]>wrote:
>
>> Try this in BGP config for VRF one:
>>
>> redist ospf 2 vrf one match internal external
>>
>> --
>> Marko Milivojevic - CCIE #18427
>> Senior Technical Instructor - IPexpert
>>
>> Mailto: [email protected]
>> Telephone: +1.810.326.1444
>> Fax: +1.810.454.0130
>> Web: http://www.ipexpert.com/
>>
>> On Mon, Mar 15, 2010 at 21:07, venkat <[email protected]> wrote:
>> > Hi,
>> > I am stuck with a problem. In the below topology;
>> > CE1------PE1----- MPLS---- PE2----CE2
>> > CE1 is sending OSPF type-5 external LSA (generated by a redistributing
>> > specific loopback IP) and i could see this lsa in PE1's ospf database.
>> But,
>> > not in BGP vpnv4 table. Is this expected behavior? I though as the
>> tag=0,by
>> > default, E2 routes are not redistributed into BGP vpnv4. tried with
>> changing
>> > tag value to 100 and still no success.
>> > Below is the configuration;
>> > <snip from R0-CE1>
>> >                 Type-5 AS External Link States
>> > Link ID         ADV Router      Age         Seq#       Checksum Tag
>> > 22.22.22.22     100.100.100.100 463         0x80000001 0x003B17 100
>> > <From R1 - PE1>
>> > OSPF 1 VRF
>> >                 Type-5 AS External Link States
>> > Link ID         ADV Router      Age         Seq#       Checksum Tag
>> > 22.22.22.22     100.100.100.100 715         0x80000001 0x003B17 100
>> > R2#
>> > !
>> >  address-family ipv4 vrf one
>> >   redistribute ospf 2 vrf one
>> >   no synchronization
>> >  exit-address-family
>> > R2#
>> > R2#show ip bgp  vpnv4 vrf one  <<< not seeing type-5 LSA
>> > BGP table version is 50, local router ID is 2.2.2.2
>> > Status codes: s suppressed, d damped, h history, * valid, > best, i -
>> > internal,
>> >               r RIB-failure, S Stale
>> > Origin codes: i - IGP, e - EGP, ? - incomplete
>> >    Network          Next Hop            Metric LocPrf Weight Path
>> > Route Distinguisher: 1:1 (default for vrf one)
>> > *> 11.1.1.0/24      0.0.0.0                  0         32768 ?
>> > *> 12.1.1.0/24      0.0.0.0                  0         32768 ?
>> > *>i13.1.1.0/24      5.5.5.5                  0    100      0 ?
>> > *>i13.1.2.0/24      5.5.5.5                  0    100      0 ?
>> > *> 100.100.100.100/32
>> >                     12.1.1.2                 2         32768 ?
>> > *>i192.168.2.0      5.5.5.5                  2    100      0 ?
>> > R2#
>> > Thanks,
>> > Venkat
>> > http://ippoint.wordpress.com/
>> >
>> > _______________________________________________
>> > For more information regarding industry leading CCIE Lab training,
>> please
>> > visit www.ipexpert.com
>> >
>> >
>>
>
>
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