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, tools, and much more.

Current Customers and Partners

Log in for full access

Log In

New to Red Hat?

Learn more about Red Hat subscriptions

Using a Red Hat product through a public cloud?

How to access this content