Guest

Preview Tool

Cisco Bug: CSCvh83686 - BGP Link Bandwidth community gets corrupted for a large values

Last Modified

Oct 30, 2019

Products (20)

  • Cisco IOS
  • Cisco ASR 901-6CZ-F-D Router
  • Cisco ASR 901-6CZ-FS-D Router
  • Cisco ME 3600X-24TS-M Switch
  • Cisco ASR 901S-4SG-F-D Router
  • Cisco ASR 901-4C-FT-D Router
  • Cisco ASR 901S-2SG-F-AH Router
  • Cisco ASR 901S-2SG-F-D Router
  • Cisco ASR 901-6CZ-F-A Router
  • Cisco ASR 901-6CZ-FT-A Router
View all products in Bug Search Tool Login Required

Known Affected Releases

15.5(3)S

Description (partial)

Symptom:
Customer reported that for a large values (i.e. 20Gb) a Link Bandwidth community by XE 3.16.6S is advertised incorrectly. For a smaller values (1Gb or even 10Gb) the Link Bandwidth community is advertised correctly.

For the large values, it receives (from XR) a Link Bandwidth community formatted correctly, but advertise it incorrectly:

*** XR sends Link BW community set to 20Gb correctly ***

            Carried extended communities: (1 community)
                Link Bandwidth: ASN 65444, 20000.000 Mbps [Non-Transitive 2-Octet AS-Specific]
                    Type: Non-Transitive 2-Octet AS-Specific (0x40)
                    Subtype (Non-transitive AS2): Link Bandwidth (0x04)
                    2-Octet AS: 65444
                    Link bandwidth: 2.5e+09 <--- HEX (4f 15 02 f9) & BIN (01001111 00010101 00000010 11111001)

*** XE sends Link BW community set to incorrect value ***

            Carried extended communities: (2 communities)
                Unknown subtype 0x06: 0:3470129678 [Transitive 2-Octet AS-Specific]
                    Type: Transitive 2-Octet AS-Specific (0x00)
                    Subtype (AS2): Unknown (0x06)
                    2-Octet AS: 0
                    4-Octet AN: 3470129678
                Link Bandwidth: ASN 0, -14359.738 Mbps [Non-Transitive 2-Octet AS-Specific]
                    Type: Non-Transitive 2-Octet AS-Specific (0x40)
                    Subtype (Non-transitive AS2): Link Bandwidth (0x04)
                    2-Octet AS: 0
                    Link bandwidth: -1.79497e+09 <- HEX (ce d5 fa 0e) & BIN (11001110 11010101 11111010 00001110)


See the link below to calculate the correct value for single-precision floating-point format:
https://www.h-schmidt.net/FloatConverter/IEEE754.html

Conditions:
- issue were seen only on IOS based devices (including XE)
Bug details contain sensitive information and therefore require a Cisco.com account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.