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[MPLS-OPS] tag-switching mtu command on cisco IOS

  • From: =?ks_c_5601-1987?B?yKvI8byu?= <hshong@innet.co.kr>
  • Date: Mon, 16 Feb 2004 11:06:27 +0900
  • Resent-Date: Sun, 15 Feb 2004 21:38:02 -0500
  • Thread-Index: AcP0MVIVk5YTyld0T8qPZeIOfi7sSg==
  • Thread-Topic: [MPLS-OPS] tag-switching mtu command on cisco IOS
  • To: <mpls-ops@mplsrc.com>

Title: CCIE Logo ΖνΑφΑφ
Hi Everyone~~
 
I have a question about cisco's " tag-switching mtu" command.
Please let me know the good answer and reason...
 
-----------------------------------------------------------------------------
(( Diagram ))
 
 --[IP Network]----(e0/0) "CISCO ROUTER" (e0/1)----[ MPLS Network ]----
 
(( Situation -1 ))
(1) Configuration
     - IP datagram mtu on e0/1 = 1500 Byte (Default Configuration)
     - "tag-swtiching mtu 1504" on e0/1 interface.
 
(2) IP Packet Arrived from e0/0
     -Size : 1500-Byte 
     -DF Bit Set : No 
     -Forwarding Interface : e0/1 
     -1 Label will be imposed.(4 byte overhead)
 
Will the Cisco router fragment this IP packet before sending it to e0/1?
or send 1504 Labeled packet without fragmentation. ( override IP mtu 1500 )
 
(( Situation -2 ))
(1) Same Configuration, Same Diagram to Situation-1
(2) IP Packet Arrived from e0/0
     -Size : 1500-Byte 
     -DF Bit Set : No 
     -Forwarding Interface : e0/1 
     -2 Label will be imposed.(8 byte overhead ..)
 
Will the Cisco router fragment this IP packet before sending it to e0/1?
-----------------------------------------------------------------------------
 
Thanks
Best Regards.
 
 
==================================================
Huisuk Hong
System Engineering
==================================================