bgp Neighbor some times lost connection

Question

unstable BGP connection

I notice that bdp  lost Neighbhor connection
Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down    State/PfxRcd    NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
10.0.0.57      4  64600        117        206         0      0       0  00:00:49   1               ARISTA01T1
10.0.0.59      4  64600        156        237         0      0       0  00:00:33   Connect         ARISTA02T1
10.0.0.61      4  64600        161        238         0      0       0  00:00:53   1               ARISTA03T1
10.0.0.63      4  64600        117        184         0      0       0  00:00:02   1               ARISTA04T1

But after a couple of seconds, another neighbor lost the connection

   Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down    State/PfxRcd    NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
10.0.0.57      4  64600        166        269         0      0       0  00:00:37   1               ARISTA01T1
10.0.0.59      4  64600        178        262         0      0       0  00:00:16   1               ARISTA02T1
10.0.0.61      4  64600        209        301         0      0       0  00:00:35   1               ARISTA03T1
10.0.0.63      4  64600        147        224         0      0       0  00:00:50   Connect         ARISTA04T1

The problem there is that for some reason some Neighbors lost connection during the session The connection is unstable . For example, the second lost connection and after couple seconds it restores the connection but the fourth neighbor lost it . Not sure how to debug such issue or fix it

Answer 1

Normally, a BGP Notification will be sent--that message contains info on why the connection dropped. Typically, it is "hold time expired" due to an unreliable datalink. Try running a constant traceroute from peer addr to peer addr while connection bounces (could be a routing issue--e.g. does bgp advertise path to peer itself?).