Well, if you work it out: Obviously the first three octets wil be all 1's, so if you look at the last octet:
11111110 Which = 254. This only leaves you with 2 addresses per subnet, and since you need one address for the Network address and one for the Broadcast address, you no longer have any addresses you can actually use. A 30 bit subnet, where the last octet= 11111100 Equals 252. This means you have 4 addresses per subnet. Taking away one address for the Network and one for the Broadcast address, this leaves you one address for each end of the link. So I am not sure how you could use a /31. Symon -----Original Message----- From: bbfaye [mailto:[EMAIL PROTECTED]] Sent: 12 October 2002 14:54 To: [EMAIL PROTECTED] Subject: can I use a /31 subnet to the link between 2 routers eth ports. [7:55450] I used thought it shoul be /30 mask subnet... but recently I saw some guy said: use /31 subnet to save the address.... I really confusing me... ######################################################################## ############# Scanned for Viruses and Content and cleared by the Webvein Mail Gateway ######################################################################## ############# Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=55454&t=55454 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]