Subject: [Isis-wg] - Regarding IS-IS LSP mtu size

From: "Rajesh Hegde" <[email-masked]>
Date: Thu, 19 Jul 2001 11:34:05 +0800

Hi all,

Following are the doubts regarding the usage of size of LSP mtu

By having default size of 1497 bytes works for most of the data link types. Ex : Ethernet, FrameRelay and Serial Links where the size of the DataLink BlockSize is 1500 bytes. 
 
1 )  How it should be handled If the datalink type is POS where the default DataLinkBlockSize is     512 bytes ?

2) How the negotiation of the Hello PDUs to be done in case of FDDI and Gigabit ethernet where the DataLinkBlockSize is greater than the default size of 1497 bytes ?
(i.e Do we pad the Hello PDU to the size of DataLink Block Size or increase the LSP MTU size ? ) 
 
3) Shall the parameters L1LSPBufferSize and L2LSPBufferSize (Level 1 lsp mtu and level 2 lsp-mtu) be made configurable ?

Suppose a router with 3 interfaces 1 ethernet(Link Mtu 1500 bytes), 1 Gigabit ethernet (Link MTU is 9180 bytes), 1 POS interface (link MTU 512 bytes )

In this case how to decide the size of the LSP-mtu ?

Thanks and Regards,
Rajesh