4 byte ASNs through OpenBGPd to old Cisco IOS

[Mike Hammett <nanog () ics-il net>]

Our IX's route servers run OpenBGPd 5.5. We are having a problem with a new customer getting turned up. He's getting 
back invalid or corrupt AS Path errors. There's a network on the IX that has a four byte ASN. They're running IOS 
12.4.(15)T and is asking me if we support RFC 4893 which appears to be the 32 bit ASN specification altogether. They 
specifically highlighted this section: 


Two new attributes, AS4_PATH and AS4_AGGREGATOR, are introduced that can be used to propagate four-octet based AS path 
information across BGP speakers that do not support the four-octet AS numbers. 


Do any of you have any useful input other than they need to upgrade their IOS to something newer than 4.5 years old? 




----- 
Mike Hammett 
Intelligent Computing Solutions 
http://www.ics-il.com