[j-nsp] SRX 550 BGP Flapping

[Payam Chychi]

On Tue, Jan 30, 2018 at 9:43 PM sameer mughal <pcs.sameer1 at gmail.com> wrote:

> Thank you all for your interests.
> Following are the interface stats FYR.
>
>   Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Link-mode:
> Full-duplex, Speed: 1000mbps, BPDU Error: None,
>   MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled,
> Flow control: Disabled,
>   Auto-negotiation: Enabled, Remote fault: Online
>   Device flags   : Present Running
>   Interface flags: SNMP-Traps Internal: 0x0
>   Link flags     : None
>   CoS queues     : 8 supported, 8 maximum usable queues
>   Current address: 00:10:db:ff:10:02, Hardware address: 58:00:bb:58:35:02
>   Last flapped   : 2018-01-30 05:27:06 GMT+5 (18:48:35 ago)
>   Input rate     : 32985528 bps (6226 pps)
>   Output rate    : 29967832 bps (5722 pps)
>   Active alarms  : None
>   Active defects : None
>   Interface transmit statistics: Disabled
>
>   Logical interface ge-0/0/2.0 (Index 67) (SNMP ifIndex 520)
>     Flags: Up SNMP-Traps 0x0 Encapsulation: ENET2
>     Input packets : 222627215
>     Output packets: 167230114
>     Security: Zone: Null
>     Protocol aenet, AE bundle: reth2.0   Link Index: 0
>
> {primary:node0}
> show interfaces ge-9/0/2
> Physical interface: ge-9/0/2, Enabled, Physical link is Up
>   Interface index: 177, SNMP ifIndex: 565
>   Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Link-mode:
> Full-duplex, Speed: 1000mbps, BPDU Error: None,
>   MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled,
> Flow control: Disabled,
>   Auto-negotiation: Enabled, Remote fault: Online
>   Device flags   : Present Running
>   Interface flags: SNMP-Traps Internal: 0x0
>   Link flags     : None
>   CoS queues     : 8 supported, 8 maximum usable queues
>   Current address: 00:10:db:ff:10:02, Hardware address: 58:00:bb:58:bc:02
>   Last flapped   : 2018-01-30 03:50:09 GMT+5 (20:25:37 ago)
>   Input rate     : 0 bps (0 pps)
>   Output rate    : 0 bps (0 pps)
>   Active alarms  : None
>   Active defects : None
>   Interface transmit statistics: Disabled
>
>   Logical interface ge-9/0/2.0 (Index 89) (SNMP ifIndex 575)
>     Flags: Up SNMP-Traps 0x0 Encapsulation: ENET2
>     Input packets : 3584089
>     Output packets: 4832617
>     Security: Zone: Null
>     Protocol aenet, AE bundle: reth2.0   Link Index: 0
>
> {primary:node0}
>
>
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>
> On Wed, Jan 31, 2018 at 1:42 AM, Payam Chychi <pchychi at gmail.com> wrote:
>
>> On Tue, Jan 30, 2018 at 9:29 AM Alexander Arseniev <
>> arseniev at btinternet.com>
>> wrote:
>>
>> > Hello,
>> >
>> > BGP KA size is 19 bytes without authentication, circa 39 with. Plus IP
>> > overhead, plus Ethernet OVH - still below 100 B.
>> >
>> > SRX reth default MTU is 1500B.
>> >
>> > Are You sure that checking & setting MTU helps to fix BGP holdtime
>> expiry?
>> >
>> > I would bet that either SRX550 reth interface is saturated, or SRX550
>> > CPU is busy.
>> >
>> > HTH
>> >
>> > Thx
>> > Alex
>> >
>> >
>> > On 30/01/2018 06:25, Emille Blanc wrote:
>> > > You might want to check the MTU of the path, or ensure that pmtu is
>> > enabled.
>> > > It looks like you're using a redundant ethernet interface (reth). If
>> > you're using a non-standard MTU, make sure it is set correctly for its
>> > member interface(s).
>> > >
>> > > ________________________________________
>> > > From: juniper-nsp [juniper-nsp-bounces at puck.nether.net] On Behalf Of
>> > sameer mughal [pcs.sameer1 at gmail.com]
>> > > Sent: Monday, January 29, 2018 8:20 PM
>> > > To: juniper-nsp at puck.nether.net
>> > > Subject: Re: [j-nsp] SRX 550 BGP Flapping
>> > >
>> > > I have seen hold time error. what will be the fix on this issue?
>> > >
>> > >
>> >
>> > _______________________________________________
>> > juniper-nsp mailing list juniper-nsp at puck.nether.net
>> > https://puck.nether.net/mailman/listinfo/juniper-nsp
>> >
>>  Bgp exchanges routes, those routes get sent as an update packet, that
>> packet can fill up the size of the packet to the mtu-ip/tcp(40byte), so
>> yes, if you have mix match of mtu, your bgp session will
>> drop/reconnect/drop... (repeat) if the update pkt size gets fragmented
>>
>>
>> --
>> Payam Tarverdyan Chychi
>> Network Security Specialist / Network Engineer
>> _______________________________________________
>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>>
>
> interfaces do not look very stable... what are they connected to? What do
your logs show?
-- 
Payam Tarverdyan Chychi
Network Security Specialist / Network Engineer