BGP Remove-private-as (just traced this - Interesting)

From: Ken.Farrington@barclayscapital.com
Date: Sun Sep 28 2003 - 17:23:20 GMT-3


Hi guys,

Just set up a trace of the bgp session between two routers with one with the
remove-private-as set on.

Intresstingly enuff, when you set this, and some of the routes match the
criteria for striping off the private-as, ( I had three routes ), these
routing updates to the neighbor are sent in a SEPERATE BGP update packet
from all the other bgp routes.

Just thought i'd let you know this. :)

Frame 308 (110 on wire, 110 captured)
    Arrival Time: Sep 28, 2003 21:12:15.448486000
    Time delta from previous packet: 4.173858000 seconds
    Time relative to first packet: 79.627968000 seconds
    Frame Number: 308
    Packet Length: 110 bytes
    Capture Length: 110 bytes
Ethernet II
    Destination: 00:10:f6:a8:18:00 (00:10:f6:a8:18:00)
    Source: 00:00:0c:5c:b7:19 (00:00:0c:5c:b7:19)
    Type: IP (0x0800)
Internet Protocol, Src Addr: 142.220.100.1 (142.220.100.1), Dst Addr:
142.220.100.200 (142.220.100.200)
    Version: 4
    Header length: 20 bytes
    Differentiated Services Field: 0xc0 (DSCP 0x30: Class Selector 6; ECN:
0x00)
        1100 00.. = Differentiated Services Codepoint: Class Selector 6
(0x30)
        .... ..0. = ECN-Capable Transport (ECT): 0
        .... ...0 = ECN-CE: 0
    Total Length: 96
    Identification: 0x0006
    Flags: 0x00
        .0.. = Don't fragment: Not set
        ..0. = More fragments: Not set
    Fragment offset: 0
    Time to live: 1
    Protocol: TCP (0x06)
    Header checksum: 0xfba3 (correct)
    Source: 142.220.100.1 (142.220.100.1)
    Destination: 142.221:22 28/09/200320.100.200 (142.220.100.200)
Transmission Control Protocol, Src Port: 11014 (11014), Dst Port: 179 (179),
Seq: 2560793303, Ack: 196392832, Len: 56
    Source port: 11014 (11014)
    Destination port: 179 (179)
    Sequence number: 2560793303
    Next sequence number: 2560793359
    Acknowledgement number: 196392832
    Header length: 20 bytes
    Flags: 0x0018 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 16282
    Checksum: 0xb912 (correct)
Border Gateway Protocol
    UPDATE Message
        Marker: 16 bytes
        Length: 56 bytes
        Type: UPDATE Message (2)
        Unfeasible routes length: 0 bytes
        Total path attribute length: 18 bytes
        Path attributes
            ORIGIN: IGP (4 bytes)
                Flags: 0x40 (Well-known, Transitive, Complete)
                    0... .... = Well-known
                    .1.. .... = Transitive
                    ..0. .... = Complete
                    ...0 .... = Regular length
                Type code: ORIGIN (1)
                Length: 1 byte
                Origin: IGP (0)
            AS_PATH: 100 (7 bytes)
                Flags: 0x40 (Well-known, Transitive, Complete)
                    0... .... = Well-known
                    .1.. .... = Transitive
                    ..0. .... = Complete
                    ...0 .... = Regular length
                Type code: AS_PATH (2)
                Length: 4 bytes
                AS path: 100
                    AS path segment: 100
                        Path segment type: AS_SEQUENCE (2)
                        Path segment length: 1 AS
                        Path segment value: 100
            NEXT_HOP: 142.220.100.1 (7 bytes)
                Flags: 0x40 (Well-known, Transitive, Complete)
                    0... .... = Well-known
                    .1.. .... = Transitive
                    ..0. .... = Complete
                    ...0 .... = Regular length
                Type code: NEXT_HOP (3)
                Length: 4 bytes
                Next hop: 142.220.100.1
        Network layer reachability information: 15 bytes
            22.22.22.2/32
            55.55.55.0/25
            220.0.0.11/32

------------------------------------------------------------------------
For more information about Barclays Capital, please
visit our web site at http://www.barcap.com.

Internet communications are not secure and therefore the Barclays
Group does not accept legal responsibility for the contents of this
message. Although the Barclays Group operates anti-virus programmes,
it does not accept responsibility for any damage whatsoever that is
caused by viruses being passed. Any views or opinions presented are
solely those of the author and do not necessarily represent those of the
Barclays Group. Replies to this email may be monitored by the Barclays
Group for operational or business reasons.

------------------------------------------------------------------------

***Get your CCIE and a FREE vacation: Shop.GroupStudy.com***



This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:39 GMT-3