SCTP congestion caused by packets disodering on br-int interface

Solution In Progress - Updated -

Issue

  • On OVS compute , VM are installed. SCTP congestion is caused leading to performance problems:
10:20:56.904434 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [SACK] [cum ack 3540453498] [a_rwnd 2095472] [#gap acks 0] [#dup tsns 0] 
10:20:56.907316 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756424] [a_rwnd 7997752] [#gap acks 0] [#dup tsns 0] , (2) [DATA] (B)(E) [TSN: 3540453499] [SID: 29] [SSEQ 4051] [PPID 0x0] , (3) [DATA] (B)(E) [TSN: 3540453500] [SID: 30] [SSEQ 4051] [PPID 0x0] 
10:20:56.907505 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [SACK] [cum ack 3540453500] [a_rwnd 2096312] [#gap acks 0] [#dup tsns 0] , (2) [DATA] (B)(E) [TSN: 2724756545] [SID: 23] [SSEQ 4036] [PPID 0x0] 
10:20:56.907527 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [DATA] (B)(E) [TSN: 2724756546] [SID: 24] [SSEQ 4036] [PPID 0x0] 
10:20:56.911712 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756426] [a_rwnd 7996628] [#gap acks 0] [#dup tsns 0] 
10:20:56.911715 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756428] [a_rwnd 7995504] [#gap acks 0] [#dup tsns 0] 
10:20:56.911813 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756430] [a_rwnd 7997752] [#gap acks 0] [#dup tsns 0] , (2) [DATA] (B)(E) [TSN: 3540453501] [SID: 31] [SSEQ 4051] [PPID 0x0] 
10:20:56.911879 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [DATA] (B)(E) [TSN: 2724756547] [SID: 25] [SSEQ 4036] [PPID 0x0] 
10:20:56.911927 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [DATA] (B)(E) [TSN: 2724756548] [SID: 26] [SSEQ 4036] [PPID 0x0] 
10:20:56.911955 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [DATA] (B)(E) [TSN: 2724756549] [SID: 27] [SSEQ 4036] [PPID 0x0] 
10:20:56.911975 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756432] [a_rwnd 7997752] [#gap acks 0] [#dup tsns 0] 
10:20:56.911984 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [DATA] (B)(E) [TSN: 2724756550] [SID: 28] [SSEQ 4036] [PPID 0x0] 
10:20:56.911990 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756434] [a_rwnd 7998876] [#gap acks 0] [#dup tsns 0] 
10:20:56.911993 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756436] [a_rwnd 7998876] [#gap acks 0] [#dup tsns 0] 
10:20:56.911996 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756438] [a_rwnd 7998876] [#gap acks 0] [#dup tsns 0] 
10:20:56.912006 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756440] [a_rwnd 7997752] [#gap acks 0] [#dup tsns 0] , (2) [DATA] (B)(E) [TSN: 3540453502] [SID: 0] [SSEQ 4216] [PPID 0x0] 
10:20:56.912012 IP 10.10.10.11.55375 > 10.10.10.10.3868: sctp (1) [SACK] [cum ack 2724756442] [a_rwnd 7998876] [#gap acks 0] [#dup tsns 0] 
10:20:56.912381 IP 10.10.10.10.3868 > 10.10.10.11.55375: sctp (1) [SACK] [cum ack 3540453501] [a_rwnd 2096732] [#gap acks 0] [#dup tsns 0] , (2) [DATA] (B)(E) [TSN: 2724756551] [SID: 29] [SSEQ 4036] [PPID 0x0] 
  • On taking TCPdump , tap & qbr interfaces packets are ordered but when reached br-int , packets are out of order leading to congestion
    security group used for VM allows all.

Environment

  • Red Hat OpenStack Platform 10.0 (RHOSP)

Subscriber exclusive content

A Red Hat subscription provides unlimited access to our knowledgebase of over 48,000 articles and solutions.

Current Customers and Partners

Log in for full access

Log In