MPLS MTU Settings

[DanielGutierrez615]

how can I get the MTU setting to reflect on the  SHOW MPLS FORWARDING DETAIL  command output, but I set up mtu 9600 on all production interfaces plus the bridge domain, but if you look at the output it still showing 1500. any advice ?

RP/0/RP0/CPU0:SCTLAB-NCS540-01#SHOW mpls forwarding interface hundredGigE 0/0/1/1 detail
Mon Jun 19 13:56:21.657 EDT
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
16001 16001 SR Pfx (idx 1) Hu0/0/1/1 192.168.24.5 0 (!)
Updated: Jun 17 12:53:48.518
Path Flags: 0x300 [ IDX:0 BKUP, NoFwd ]
Version: 4904, Priority: 2
Label Stack (Top -> Bottom): { 16001 }
NHID: 0x0, Encap-ID: 0x119a200000002, Path idx: 0, Backup path idx: 0, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0
(!): FRR pure backup

Traffic-Matrix Packets/Bytes Switched: 0/0
16002 Pop SR Pfx (idx 2) Hu0/0/1/1 192.168.24.5 0
Updated: Jun 17 12:53:48.498
Path Flags: 0x400 [ BKUP-IDX:1 (0x8a0051b0) ]
Version: 4877, Priority: 2
Label Stack (Top -> Bottom): { Imp-Null }
NHID: 0x0, Encap-ID: 0x118a300000002, Path idx: 0, Backup path idx: 1, Weight: 0
MAC/Encaps: 14/14, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0

RP/0/RP0/CPU0:SCTLAB-NCS540-01#show interfaces | include MTU 9600
Mon Jun 19 13:56:04.165 EDT
MTU 9600 bytes, BW 10000000 Kbit (Max: 10000000 Kbit)
MTU 9600 bytes, BW 10000000 Kbit (Max: 10000000 Kbit)
MTU 9600 bytes, BW 10000000 Kbit (Max: 10000000 Kbit)
MTU 9600 bytes, BW 10000000 Kbit (Max: 10000000 Kbit)

bridge group NEXUS_CORE
bridge-domain VM_CORE_MGMT
mtu 9216
interface TenGigE0/0/0/0.248
!
interface TenGigE0/0/0/2.248

!
routed interface BVI248
!
evi 5248

########################################################

[MHM Cisco World]

I think you need to use mpls mtu not mtu.

[DanielGutierrez615]

That's what I'm running

 interface HundredGigE0/0/1/1
description CEL-RTR-C02-01, Hu0/0/0/15
cdp
mtu 9600
ipv4 address 192.168.24.6 255.255.255.252
mpls
mtu 9600
!
!

[MHM Cisco World]

I will check 

[MHM Cisco World]

 interface HundredGigE0/0/1/1
description CEL-RTR-C02-01, Hu0/0/0/15
cdp
mtu 9600 <<- this jumbo frame 
ipv4 address 192.168.24.6 255.255.255.252
mpls mtu 9560 <<- must less than MTU 

share 
show mpls forwarding detail <<- this give you MRU check it value.

[DanielGutierrez615]

This is NCS540   version 7.6.2  

RP/0/RP0/CPU0:SCTLAB-NCS540-01#SHOW RUN INT HUndredGigE 0/0/1/1
Mon Jun 19 16:00:40.382 EDT
interface HundredGigE0/0/1/1
description CEL-RTR-C02-01, Hu0/0/0/15
cdp
mtu 9600
ipv4 address 192.168.24.6 255.255.255.252
mpls
mtu 9560
!
!

RP/0/RP0/CPU0:SCTLAB-NCS540-01#show mpls forwarding interface hundredGigE 0/0/1/1 detail | include MTU
Mon Jun 19 16:00:27.139 EDT
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/18, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500
MAC/Encaps: 14/14, MTU: 1500

[MHM Cisco World]

Show mpls forwarding-table detail 

What is mru value for ldp neighbor?

[DanielGutierrez615]

This cisco device does not support that command. but if I do show im database interface hundredGigE 0/0/1/1, it reflect the changes, but still when I push traffic with a higher MTU 1522  it drops the traffic.  I'm reading this article  to see if I find an answer. https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/ios-xr-software/116350-trouble-ios-xr-mtu-00.html

RP/0/RP0/CPU0:SCTLAB-NCS540-01#Show mpls forwarding ?
debug Include debug information(cisco-support)
detail Detailed information
exact-route Display exact path for source/dest addr pair
fast-reroute Display protected label entries only
interface Match outgoing interface
label-security Display label security information
labels Match label values
location Specify a location
lsm-id p2mp mldp LSM ID database
no-counters Skip displaying counters(cisco-support)
p2mp p2mp lsps only
p2p p2p lsps only
prefix Match destination prefix and mask
private Include private information(cisco-support)
rpf Display label RPF info
summary Summarized information
tunnels TE tunnel(s) at head
vrf Show entries for a VPN Routing/Forwarding instance
| Output Modifiers.

RP/0/RP0/CPU0:SCTLAB-NCS540-01#show im database interface hundredGigE 0/0/1/1
Mon Jun 19 16:22:44.352 EDT

View: OWN - Owner, L3P - Local 3rd Party, G3P - Global 3rd Party, LDP - Local Data Plane
GDP - Global Data Plane, RED - Redundancy, UL - UL

Node 0/0/CPU0 (0x0)

Interface HundredGigE0/0/1/1, ifh 0x00000028 (up, 9600)
Interface flags: 0x000000000110049f (ROOT_IS_HW|IFCONNECTOR
|IFINDEX|BROADCAST|CONFIG|HW|VIS|DATA|CONTROL)
Encapsulation: ether
Interface type: IFT_HUNDREDGE
Control parent: None
Data parent: None
Views: GDP|LDP|L3P|OWN

Protocol Caps (state, mtu)
-------- -----------------
None hw_oor (up, 9600)
None spio (up, 9600)
None ether (up, 9600)
arp arp (up, 9586)
clns clns (up, 9586)
ipv4 ipv4 (up, 9586)
mpls mpls (up, 9560)
ether_sock ether_sock (up, 9586)

[MHM Cisco World]

Show mpls forwarding details 

[DanielGutierrez615]

This is the same output I posted earlier, but only included the MTU

here is the the full output 

RP/0/RP0/CPU0:SCTLAB-NCS540-01#show mpls FOrwarding interface hundredGigE 0/0/1/1 detail
Mon Jun 19 16:36:39.406 EDT
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
16001 16001 SR Pfx (idx 1) Hu0/0/1/1 192.168.24.5 0 (!)
Updated: Jun 19 16:00:05.845
Path Flags: 0x300 [ IDX:0 BKUP, NoFwd ]
Version: 5322, Priority: 2
Label Stack (Top -> Bottom): { 16001 }
NHID: 0x0, Encap-ID: 0x119a200000002, Path idx: 0, Backup path idx: 0, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0
(!): FRR pure backup

Traffic-Matrix Packets/Bytes Switched: 0/0
16002 Pop SR Pfx (idx 2) Hu0/0/1/1 192.168.24.5 0
Updated: Jun 19 16:00:05.826
Path Flags: 0x400 [ BKUP-IDX:1 (0x8a005390) ]
Version: 5295, Priority: 2
Label Stack (Top -> Bottom): { Imp-Null }
NHID: 0x0, Encap-ID: 0x118a300000002, Path idx: 0, Backup path idx: 1, Weight: 0
MAC/Encaps: 14/14, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0

Traffic-Matrix Packets/Bytes Switched: 0/0
16003 16003 SR Pfx (idx 3) Hu0/0/1/1 192.168.24.5 0
Updated: Jun 19 16:00:05.825
Path Flags: 0x400 [ BKUP-IDX:1 (0x8a005390) ]
Version: 5294, Priority: 2
Label Stack (Top -> Bottom): { 16003 }
NHID: 0x0, Encap-ID: 0x118ba00000002, Path idx: 0, Backup path idx: 1, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0

Traffic-Matrix Packets/Bytes Switched: 0/0
16015 16015 SR Pfx (idx 15) Hu0/0/1/1 192.168.24.5 3959
Updated: Jun 19 16:00:05.826
Path Flags: 0x400 [ BKUP-IDX:1 (0x8a005390) ]
Version: 5296, Priority: 2
Label Stack (Top -> Bottom): { 16015 }
NHID: 0x0, Encap-ID: 0x118a800000002, Path idx: 0, Backup path idx: 1, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 74

Traffic-Matrix Packets/Bytes Switched: 0/0
16101 16101 SR Pfx (idx 101) Hu0/0/1/1 192.168.24.5 0 (!)
Updated: Jun 19 16:00:05.845
Path Flags: 0x300 [ IDX:0 BKUP, NoFwd ]
Version: 5324, Priority: 2
Label Stack (Top -> Bottom): { 16101 }
NHID: 0x0, Encap-ID: 0x119a600000002, Path idx: 0, Backup path idx: 0, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0
(!): FRR pure backup

Traffic-Matrix Packets/Bytes Switched: 0/0
16103 16103 SR Pfx (idx 103) Hu0/0/1/1 192.168.24.5 0
Updated: Jun 19 16:00:05.826
Path Flags: 0x400 [ BKUP-IDX:1 (0x8a005390) ]
Version: 5297, Priority: 2
Label Stack (Top -> Bottom): { 16103 }
NHID: 0x0, Encap-ID: 0x118bc00000002, Path idx: 0, Backup path idx: 1, Weight: 0
MAC/Encaps: 14/18, MTU: 1500
Outgoing Interface: HundredGigE0/0/1/1 (ifhandle 0x00000028)
Packets Switched: 0

[MHM Cisco World]

1-

Protocol Caps (state, mtu)
-------- -----------------
None hw_oor (up, 9600)
None spio (up, 9600)
None ether (up, 9600)
arp arp (up, 9586)
clns clns (up, 9586)
ipv4 ipv4 (up, 9586)
mpls mpls (up, 9560)<<- you config and the NSC accept the value 
ether_sock ether_sock (up, 9586)

2-RP/0/RP0/CPU0:SCTLAB-NCS540-01#Show mpls forwarding ?
debug Include debug information(cisco-support)
detail Detailed information

I need to see the MRU

[Harold Ritter]

Hi @DanielGutierrez615 ,

This looks like a cosmetic bug. It will not have any impact on MPLS traffic. To see the real MPLS mtu size, you can use the following command: 

show imds interface <interface name>

or

show mpls interfaces <interface name> private location <location>

You can also use the "traceroute mpls" to see the effective MRU of each link across the LSP between the ingress and egress PE.

PE1#traceroute mpls ipv4 192.168.100.4/32 source 192.168.100.1
Tracing MPLS Label Switched Path to 192.168.100.4/32, timeout is 2 seconds

Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0

Type escape sequence to abort.
0 192.168.12.1 MRU 9202 [Labels: 24002 Exp: 0]
L 1 192.168.12.2 MRU 9202 [Labels: 19 Exp: 0] 53 ms
L 2 192.168.23.3 MRU 9206 [Labels: implicit-null Exp: 0] 11 ms
! 3 192.168.34.4 18 ms
PE1#

Regards,