Ann, the commas not withstanding, the le/ge operands as applicable to prefix-lists simply mean "less-than or equal-to" or greater-than or "equal-to" wrt netmasks in CIDR speak. In you prefix-list below, the le operand means - allow following ranges: /22,/23,/24 deny all else for the /21 it means allow /21 thru /24 Anything without an operand means an exact-match(permit/deny) Homework for you: What do the following do: 1) ip prefix-list foo deny 0.0.0.0/0 le32 2) ip prefix-list foo permit 0.0.0/0 le 32 Understand the above and you will understand how operands work in prefix-lists. ./Randy --- On Wed, 2/1/12, Ann Kwok <annkwok80@gmail.com> wrote:
From: Ann Kwok <annkwok80@gmail.com> Subject: Question about prefix list To: nanog@nanog.org Date: Wednesday, February 1, 2012, 6:32 AM Hi
I read this prefix list.
Can I know why there is "le 24" after network block in /22 and /21
Why don't have "le 24" after /24?
I also saw another prefix list before. They use "le 32" instead of "le 24"
What are their different?
ip prefix-list prefix-filter-as100 seq 10 permit 202,168.136.0/22 le 24 ip prefix-list prefix-filter-as100 seq 20 permit 202,22.92.0/22 le 24 ip prefix-list prefix-filter-as100 seq 30 permit 202,21.148.0/22 le 24 ip prefix-list prefix-filter-as100 seq 40 permit 203,178.88.0/21 le 24 ip prefix-list prefix-filter-as100 seq 50 permit 178.88.74.0/24
Thank you so much