Interop MTUs

Inter-op MTU sizes. The "Usable MTU" represents the maximum size for the payload part of an Ethernet frame.

+----------------------------+----------------------------+-----------------------+--------------------------+------------+
| Device Tested On           | Includes Ethernet headers  | Includes MPLS headers | Configured interface MTU | Usable MTU |
|                            |    in interface setting    |                       |                          |            |
+----------------------------+----------------------------+-----------------------+--------------------------+------------+
| Cisco IOS (7600)           | Y                          | Y                     | 9000                     | 9000       |
| Cisco IOS (ME3600) EVC     |                            |                       |                          |            |
| Cisco IOS-XR (ASR9K)       | N                          | Y                     | 9014                     | 9000       |
| Juniper JUNOS (MX480)      | N                          | Y                     | 9014                     | 9000       |
+----------------------------+----------------------------+-----------------------+--------------------------+------------+

Inter-op ping command sizes. The IOS ping command will account the Ethernet headers, IOS-XR command expects them to be removed, Junos expects all headers upto the ICMP payload to be removed.

+----------------------------+----------------------------+-------------------------------------+
| Device Tested On           |    MTU size on interface   |    Max size usable with             |
|                            |                            |    "ping" cmd and df-bit            |
+----------------------------+----------------------------+-------------------------------------+
| Cisco IOS (7600)           | 9000                       | 9000                                |
| Cisco IOS (ME3600) EVC     |                            |                                     |
| Cisco IOS-XR (ASR9K)       | 9014                       | 9000 (-14 Ethernet)                 |
| Juniper JUNOS (MX480)      | 9000                       | 8958 (-14 Ethernet, -20 IP, -8 ICMP)|
+----------------------------+----------------------------+-------------------------------------+

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