[j-nsp] EX4550 (Un-)known unicast flooding at session start for up to 100ms

[Pavel Lunin]

Not sure this is specifically related to the OP but there is a known
hardware limitation/feature of some Broadcom chips used in many EX switches
of the previous generations (including EX4500). They use a hash table to
reduce MAC lookup length, which was too small in some older JUNOS versions,
leading to hash-collisions and consequent mac learning failures in some
scenarios.

Links, worth to check:

https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/mac-lookup-length-edit-ethernet-switching-options.html
https://forums.juniper.net/t5/Ethernet-Switching/EX4500-show-ethernet-switching-hash-collisions/td-p/204849
https://yingsnotebook.wordpress.com/2017/03/20/mac-address-learning-problem-in-juniper-ex-switch/




2017-08-12 2:14 GMT+02:00 Aaron Gould <aaron1 at gvtc.com>:

> Sorry to hear that.
>
> I may have mentioned previously to someone else on the list... my EX4550's
> are rock solid... over 4 years uptime... I run our mirrored/redundant data
> centers behind them (hp 3par, hypervisors, etc) and our internet cdn caches
> behind them too...(Akamai, netflix, and that other one)
>
> A pair of 4550's in top of racks virtual chassis'ed together
>
> Here they are...
>
> root at sabn-dcvc-4550> show system uptime | grep "up|fpc"
> fpc0:
> 7:07PM  up 1516 days,  5:51, 0 users, load averages: 0.09, 0.11, 0.08
> fpc1:
> 7:07PM  up 1516 days,  5:51, 2 users, load averages: 0.22, 0.17, 0.16
>
>
> root at stlr-dcvc-4550> show system uptime | grep "up|fpc"
> fpc0:
> 7:09PM  up 1520 days,  4:21, 0 users, load averages: 0.11, 0.15, 0.14
> fpc1:
> 7:09PM  up 1520 days,  4:42, 1 user, load averages: 0.25, 0.22, 0.18
>
>
> root at stlr-dcvc-4550> show version | grep "fpc|model|boot"
> fpc0:
> --------------------------------------------------------------------------
> Model: ex4550-32f
> JUNOS Base OS boot [12.2R4.5]
> fpc1:
> --------------------------------------------------------------------------
> Model: ex4550-32f
> JUNOS Base OS boot [12.2R4.5]
>
> ....run a bunch of vlans/stp...
>
> {master:1}
> root at stlr-dcvc-4550> show spanning-tree bridge brief | grep
> "protocol|Vlan"
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 12
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 1000
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 10
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 11
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 210
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 204
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 202
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 201
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 14
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 13
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 1006
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 101
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 921
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 2
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 2202
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 3
> Enabled protocol                    : RSTP
>
> STP bridge parameters for VLAN 4
>
>
>
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