[j-nsp] mx960 to mx960 via ciena 6500 - mtu smaller in the middle

[Aaron Gould]

See juniper interface MTU is set to max 16000 bytes. but when I ping I can
only get 9584 bytes through to the other side of the link.  This mx960 is
linked to another mx960, but Ciena 6500 dwdm is in between the mx960's.

 

Is there any reason why I should be concerned that currently Ciena tells us
that they only support 9600 byte MTU and that I have 16000 set on my MX960's
?

 

Is there an issue that could arise with this scenario ?

 

Currently ospf and ldp are neighboring fine and advertising routes and
labels

 

Ciena TAC mentioned that future upgrades may enable larger mtu's.

 

agould at 960> show arp interface ae0.0

MAC Address       Address         Name                      Interface
Flags

d0:07:ca:zz:yy:xx 10.101.129.13   10.101.129.13             ae0.0
none

 

agould at 960> show configuration interfaces ae0 | display set

set interfaces ae0 mtu 16000

set interfaces ae0 aggregated-ether-options lacp active

set interfaces ae0 unit 0 family inet address 10.101.129.14/30

set interfaces ae0 unit 0 family mpls

 

agould at 960> show interfaces ae0.0 | grep mtu

    Protocol inet, MTU: 15986

    Protocol mpls, MTU: 15974, Maximum labels: 3

    Protocol multiservice, MTU: Unlimited

 

agould at 960> show lacp interfaces ae0

Aggregated interface: ae0

..

      et-0/0/2                  Current   Fast periodic Collecting
distributing

 

agould at 960> show interfaces et-0/0/2 | grep mtu

  Link-level type: Ethernet, MTU: 16000, MRU: 16008, Speed: 100Gbps, BPDU
Error: None, Loop Detect PDU Error: None,

 

agould at 960> ping 10.101.129.13 rapid size 9584

PING 10.101.129.13 (10.101.129.13): 9584 data bytes

!!!!!

--- 10.101.129.13 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max/stddev = 3.169/3.622/4.646/0.524 ms

 

agould at 960> ping 10.101.129.13 rapid size 9585

PING 10.101.129.13 (10.101.129.13): 9585 data bytes

.....

--- 10.101.129.13 ping statistics ---

5 packets transmitted, 0 packets received, 100% packet loss

 

- Aaron