[c-nsp] ASR 9922 IOS-XR 4.3.1

[Harvey Young]

Hello Experts,

Question:

How is the T Spec MTU set on the ASR? I am running into a wall, the ASR
sends T Spec mtu of 500 for an RSVP LSP. However, 500 is not set anywhere.
I have the following MTU set: (Including snip bits from configuration, see
below)

Essentially the setup is an RSVP-TE LSP and a L2PW utilizing the LSP. The
remote end is sending 9198, however since the ASR is sending 500, 500 the
lower mtu is negotiated and used.

<cisco-nsp at puck.nether.net>HundredGigE0/1/0/0 is Up, ipv4 protocol is Up
  Vrf is default (vrfid 0x60000000)
  Internet address is 13.1.1.1/24
  MTU is 9212 (9198 is available to IP)


RP/0/RP0/CPU0:ios#show running-config interface
Tue Jul 30 18:02:22.481 UTC
interface Loopback1
 ipv4 address 1.1.1.1 255.255.255.255
!
interface tunnel-te1
 ipv4 unnumbered Loopback1
 mpls
  mtu 9198
 !
 destination 7.7.7.7
 path-option 1 dynamic
!
interface HundredGigE0/1/0/0
 mtu 9212
 ipv4 address 13.1.1.1 255.255.255.0
 mpls
  mtu 9198
 !
interface HundredGigE0/1/0/1.1 l2transport
 encapsulation dot1q 1 second-dot1q 1
 mtu 1528
!
RP/0/RP0/CPU0:ios#show running-config l2vpn
Tue Jul 30 18:04:05.107 UTC
l2vpn
 router-id 1.1.1.1
 pw-class 1
  encapsulation mpls
   protocol ldp
   preferred-path interface tunnel-te 1
  !
 !
 xconnect group 1
  p2p 1
   interface HundredGigE0/1/0/1.1
   neighbor ipv4 7.7.7.7 pw-id 1
    pw-class 1
   !
mpls traffic-eng
 interface tunnel-te1
 !
 interface HundredGigE0/1/0/0
 !
 attribute-set path-option 1
 !
!
mpls ldp
 neighbor 7.7.7.7 targeted
!

rsvp
 interface Loopback1
 !
 interface tunnel-te1
  bandwidth percentage 100
 !
 interface HundredGigE0/1/0/0
 !
!

Trace from remote system:


Recv PATH From:1.1.1.1, To:7.7.7.7
          TTL:255, Checksum:0x25f1, Flags:0x1
Session    - EndPt:7.7.7.7, TunnId:1, ExtTunnId:1.1.1.1
SessAttr   - Name:ios_t1
             SetupPri:7, HoldPri:7, Flags:0x4
RSVPHop    - Ctype:1, Addr:13.1.1.1, LIH:100663488
TimeValue  - RefreshPeriod:45
SendTempl  - Sender:1.1.1.1, LspId:12
SendTSpec  - Ctype:QOS, CDR:0.000 bps, PBS:8.000 Kbps, PDR:0.000 bps
             MPU:40, *MTU:500* <------
LabelReq   - IfType:General, L3ProtID:2048
ERO        - IPv4Prefix 13.1.1.2/32, Strict
             IPv4Prefix 7.7.7.7/32, Strict
AdSpec     - General BreakBit:0, NumISHops:1, PathBwEstimate:0
                     MinPathLatency:0, CompPathMTU:9198
             Controlled BreakBit:0