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Beginner

MPLS LDP - NSR N/A

Hello all,

After upgrading an ASR9K from 4.0.1 to 4.2.3 I noticed that NSR didn't came up, showing N/A in the output of "sh mpls ldp neighbor brief":

RP/0/RSP0/CPU0:A9K-LAB01#sh mpls ldp neighbor brief      

Fri Jan  4 14:19:52.393 WET

Peer               GR  NSR  Up Time     Discovery  Address  IPv4 Label

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

172.25.200.7:0     Y   Y    6w2d                2        3          10 <- IOS

172.25.200.2:0     Y   Y    3w4d                3       12          10 <- IOS

172.25.200.10:0    Y   Y    2w0d                2        4          31 <- IOS-XR 4.0.1

172.25.200.11:0    Y   N/A  20:55:55            1        4          31 <- IOS-XR 4.2.3

172.25.200.6:0     Y   N/A  02:08:11            1        7          31 <- IOS-XR 4.2.3

172.25.200.15:0    Y   N/A  00:12:37            2        3          31 <- IOS-XR 4.2.3

Routers have connectivity to each other, and configurations are pretty much the same in all of them:

RP/0/RSP0/CPU0:A9K-LAB01#sh run mpls ldp

Fri Jan  4 15:45:12.164 WET

mpls ldp

router-id 172.25.200.5

discovery hello holdtime 45

discovery hello interval 15

nsr

graceful-restart

backoff 5 10

holdtime 80

session protection

neighbor 172.25.200.2 password encrypted

neighbor 172.25.200.7 password encrypted

neighbor 172.25.200.10 password encrypted

neighbor 172.25.200.15 password encrypted

igp sync delay 10

label

  allocate for LLAF

!

log

  neighbor

  graceful-restart

  session-protection

  nsr

!

interface GigabitEthernet0/4/0/0.2

!

interface TenGigE0/0/0/1.2

!

interface TenGigE0/0/0/2.2

!

interface TenGigE0/1/0/0.2

!

interface TenGigE0/1/0/1.2

!

!

RP/0/RSP0/CPU0:A9K-LAB01#

When debugging "mpls ldp nsr" in 4.2.3 I don't see any event, however in 4.0.1 I can see all the events. Anyone could help me to go further in my troubleshooting?

Thanks,

Pedro

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Accepted Solutions
Cisco Employee

MPLS LDP - NSR N/A

Hello Pedro,

may you look at show mpls ldp neighbour output and verify if these are targeted LDP sessions?

NSR on targeted LDP is supported from 4.3.0.

Regards,

/A

6 REPLIES 6
Cisco Employee

MPLS LDP - NSR N/A

Hello Pedro,

may you look at show mpls ldp neighbour output and verify if these are targeted LDP sessions?

NSR on targeted LDP is supported from 4.3.0.

Regards,

/A

Beginner

MPLS LDP - NSR N/A

Thx Alexei,

Yes, I'm aware of that detail, however this are directly connected routers.

Any other idea?

Regards,

Pedro

Cisco Employee

Re: MPLS LDP - NSR N/A

Hi Pedro,

Do you have l2vpn between these directly connected rotuers for example? If so, then even on these directly connected links we run targeted ldp and hence no NSR.

Here is the example from my lab on a directly connected link:

RP/0/RSP0/CPU0:sisters#show mpls ldp neighbor brief

Mon Jan  7 13:55:10.143 CET

Peer               GR  NSR  Up Time     Discovery  Address  IPv4 Label

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

138.187.93.66:0    Y   N/A  1w5d                2       25          89

10.0.1.25:0        Y   Y    4d02h               2       24          81

RP/0/RSP0/CPU0:sisters#show mpls ldp neighbor 138.187.93.66

Mon Jan  7 13:55:29.449 CET

Peer LDP Identifier: 138.187.93.66:0

  TCP connection: 138.187.93.66:49647 - 138.187.93.64:646

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 0 sec)

  Session Holdtime: 180 sec

  State: Oper; Msgs sent/rcvd: 20234/20274; Downstream-Unsolicited

  Up time: 1w5d

  LDP Discovery Sources:

    TenGigE0/2/0/0

    Targeted Hello (138.187.93.64 -> 138.187.93.66, active)

RP/0/RSP0/CPU0:sisters#show running-config l2vpn

Mon Jan  7 13:55:42.462 CET

l2vpn

!

xconnect group XX

  p2p YY

   interface Bundle-Ether9400.91040

   neighbor 138.187.93.66 pw-id 901040

!

Regards,

/A

Beginner

Re: MPLS LDP - NSR N/A

Hi Alexei,

Yes, we do have L2 VPNs between those routers. Also, I checked the output of "show mpls ldp neighbor" and targeted ldp is running in all of them. That is what got me confused. I believe that we might be facing any kind of cosmetic bug in the routers running 4.0.1...

RP/0/RSP0/CPU0:A9K-LAB01#sh mpls ldp neighbor brief

Mon Jan  7 15:02:07.376 WET

Peer               GR  NSR  Up Time     Discovery  Address  IPv4 Label

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

172.25.200.11:0    Y   N/A  2d23h               1        4          31

172.25.200.2:0     Y   Y    2d23h               3       12          10

172.25.200.7:0     Y   Y    2d23h               2        3          10

172.25.200.10:0    Y   Y    2d23h               2        4          31  <- 4.0.1

172.25.200.6:0     Y   N/A  2d20h               1        7          31  <- 4.2.3

172.25.200.15:0    Y   N/A  02:15:40            2        3          31

RP/0/RSP0/CPU0:A9K-LAB01#sh mpls ldp neighbor

Mon Jan  7 15:02:18.219 WET

Peer LDP Identifier: 172.25.200.11:0

  TCP connection: 172.25.200.11:19136 - 172.25.200.5:646

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 180 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 11180/11165; Downstream-Unsolicited

  Up time: 2d23h

  LDP Discovery Sources:

    Targeted Hello (172.25.200.5 -> 172.25.200.11, active)

  Addresses bound to this peer:

    172.25.7.36      172.25.7.94      172.25.7.161     172.25.200.11

Peer LDP Identifier: 172.25.200.2:0

  TCP connection: 172.25.200.2:646 - 172.25.200.5:29821; MD5 on

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 180 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 11129/11093; Downstream-Unsolicited

  Up time: 2d23h

  LDP Discovery Sources:

    TenGigE0/1/0/0.2

    TenGigE0/0/0/1.2

    Targeted Hello (172.25.200.5 -> 172.25.200.2, active)

  Addresses bound to this peer:

    172.25.7.25      172.25.7.81      172.25.7.85      172.25.7.101

    172.25.7.113     172.25.7.121     172.25.7.125     172.25.7.153

    172.25.7.157     172.25.7.173     172.25.7.177     172.25.200.2

Peer LDP Identifier: 172.25.200.7:0

  TCP connection: 172.25.200.7:39798 - 172.25.200.5:646; MD5 on

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 120 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 11133/11086; Downstream-Unsolicited

  Up time: 2d23h

  LDP Discovery Sources:

    GigabitEthernet0/4/0/0.2

    Targeted Hello (172.25.200.5 -> 172.25.200.7, active)

  Addresses bound to this peer:

    172.25.7.106     172.25.7.110     172.25.200.7

Peer LDP Identifier: 172.25.200.10:0

  TCP connection: 172.25.200.10:41025 - 172.25.200.5:646; MD5 on

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 180 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 11125/11133; Downstream-Unsolicited

  Up time: 2d23h

  LDP Discovery Sources:

    TenGigE0/0/0/2.2

    Targeted Hello (172.25.200.5 -> 172.25.200.10, active)

  Addresses bound to this peer:

    172.25.7.34      172.25.7.90      172.25.7.97      172.25.200.10

Peer LDP Identifier: 172.25.200.6:0

  TCP connection: 172.25.200.6:25373 - 172.25.200.5:646

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 0 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 11349/12751; Downstream-Unsolicited

  Up time: 2d20h

  LDP Discovery Sources:

    Targeted Hello (172.25.200.5 -> 172.25.200.6, active)

  Addresses bound to this peer:

    172.25.7.31      172.25.7.86      172.25.7.93      172.25.7.109

    172.25.7.169     172.25.7.178     172.25.200.6

Peer LDP Identifier: 172.25.200.15:0

  TCP connection: 172.25.200.15:63213 - 172.25.200.5:646; MD5 on

  Graceful Restart: Yes (Reconnect Timeout: 120 sec, Recovery: 0 sec)

  Session Holdtime: 80 sec

  State: Oper; Msgs sent/rcvd: 384/384; Downstream-Unsolicited

  Up time: 02:15:51

  LDP Discovery Sources:

    TenGigE0/1/0/1.2

    Targeted Hello (172.25.200.5 -> 172.25.200.15, active)

  Addresses bound to this peer:

    172.25.7.166     172.25.7.170     172.25.200.15

RP/0/RSP0/CPU0:A9K-LAB01#

Any place in the documentation were I can found more info about targeted LDP?

Thanks,

Pedro

Cisco Employee

Re: MPLS LDP - NSR N/A

Yes, indeed, officially NSR is not supported on targeted LDP, so even if it works, we can consider it as a bonus

There is not much difference between LDP and tLDP.  tLDP neighbour discovery differs from normal discovery only in the addressing of hello packets. Hello packets use unicast IP addresses instead of multicast addresses. When a neighbour is discovered, the mechanism to establish a session is the same.

Regards,

/A

Beginner

Re: MPLS LDP - NSR N/A

Thx for your help Alexei!!!

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