On Tue, Jun 03, 2008 at 09:15:30AM -0400, cp wrote: > I hoping someone can provide insight into why by default juniper > calculates mpls mtu at 12 bytes less than the ip mtu? I've been testing > using l3vpn and it seems that mpls mtu pads 8 bytes to its mpls mtu > reducing the ip mtu the inside packet by 8 bytes. Quick example. So if > mpls mtu is 1508 the ip mtu of the packet inside is 1500. That means the > ip mtu of the mpls interface is 1520. The only reason I can see > additional bytes needed on top of the l3vpn two is for fast reroute > bypass. I assume it's for the safety factor although I am probably > missing something. Any information is appreciated.
Exactly that's the case as far as I'm aware. They have chosen a default "enough for most usages" headroom. Then again, defaults may change, so it's good engineering practice to set MTUs for all protocols explicitly. Best regards, Daniel -- CLUE-RIPE -- Jabber: [EMAIL PROTECTED] -- [EMAIL PROTECTED] -- PGP: 0xA85C8AA0 _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
