07-10-2012 05:45 AM - edited 03-04-2019 04:55 PM
Hello guys, I'm trying to establish a BGP neighborship with my ISP using my own ASN. The thing is that AS is a 32bit AS. I read on others papers that since the IOS 12.4(24) the support for ASN 4byte(32bits) was introduced. For some reason I cant enable BGP under an AS32bits on my 2811.
Please, could someone advise?
Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(24)T1, RELEASE SOFTWARE (fc3)
BGP-AS32(config)#router bgp ?
<1-65535> Autonomous system number --> Only 16bits
<1.0-XX.YY> 4 Octets Autonomous system number
BGP-AS32(config)#router bgp 262477
^
% Invalid input detected at '^' marker
Thanks in advance.
Victor
Solved! Go to Solution.
07-10-2012 06:27 AM
Hello Victor,
the router expects you to enter the 32 bit AS number in as dot notation that is a format with a dot in the middle between two 16 bit entities
see this example
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080bc7d00.shtml
and
notice the point in the online help
<1.0-XX.YY> 4 Octets Autonomous system number
you need to convert your AS in plain text format in as dot format by dividing for 65536 the total number so that 65536 = 1.0 see the first example
Hope to help
Giuseppe
07-10-2012 06:27 AM
Hello Victor,
the router expects you to enter the 32 bit AS number in as dot notation that is a format with a dot in the middle between two 16 bit entities
see this example
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080bc7d00.shtml
and
notice the point in the online help
<1.0-XX.YY> 4 Octets Autonomous system number
you need to convert your AS in plain text format in as dot format by dividing for 65536 the total number so that 65536 = 1.0 see the first example
Hope to help
Giuseppe
07-10-2012 07:18 AM
Hello Giuseppe, thank you very much for your quickly reply. So if I understand, I need to divide my ASN for 65536, this will give a number formated as dot decimal, right?
Well I've done this and got to this number
My AS / 65536 ==> 242677/65536 = 4,005081176757813
Should I enable bgp under the 4.0 ASN ? Like this:
router bgp 4.0
In the first example, there is a line that tells me to input the bgp asnotation dot command, but I do not have this option. Take a look:
BGP-AS32#sh run | sec bgp
router bgp 4.0
no synchronization
bgp router-id 1.1.1.1
bgp log-neighbor-changes
no auto-summary
BGP-AS32(config-router)#bgp asnotation dot
^
% Invalid input detected at '^' marker.
BGP-AS32(config-router)#bgp a?
always-compare-med
Thanks again!
Victor
07-10-2012 07:24 AM
Dear Victor,
Your 4 byte ASN in ASDOT
AS in PLAIN :242677
Converted ASN: 4.333
Source : http://submit.apnic.net/cgi-bin/convert-asn.pl
HTH.
07-10-2012 08:47 AM
Dear dc-csa-blr, thank your for that link! It's really useful. Although I still have problems in this matter, since the document that Giusep suggested states that if you don't turn on the bgp asnotation dot option the router will assume that this is a plain notation (default).
(e.g.)
!--- This command change the default asplain notation
to dot notation.
!--- Note that without this command the AS number will
treated as asplain notation i.e. 10.1 will
be displayed as 655361
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080bc7d00.shtml
(...)
The problem is that I cant turn this option on.
BGP-AS32(config-router)#bgp asnotation dot
^
% Invalid input detected at '^' marker.
BGP-AS32(config-router)#bgp a?
always-compare-med
Thanks,
Victor
07-10-2012 09:37 AM
Hello Victor,
you have to enter the AS number as 4.333 according to the calculation performed by dc-csa-bir
router bgp 4.333
your IOS works only in as not notation ( my guess) so there is no command to enable it as it is already enabled
the online help of your router says it expect 4 byte AS in dot notation follow it.
Hope to help
Giuseppe
07-10-2012 10:31 AM
Thanks Giuseppe and dc-csa-blr for your replies, I really appreciate! You guys helped a lot! 5 stars each .
Victor
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: