High Availability | Junos OS Evolved

NSR faster detection of connection slowness on replication layer (PTX10004, PTX10008, and PTX10016)—Starting in Junos OS Evolved Release 23.4R1, nonstop active routing (NSR) detects connection slowness on the replication layer faster. Faster detection helps reduce the negative impact that replication layer issues can have on NSR sessions, especially those with low hold timers.

[See Nonstop Active Routing Concepts for Junos OS Evolved.]

NSR switchover support with low hold timers (PTX10004, PTX10008, and PTX10016)—Starting in Junos OS Evolved Release 23.4R1, we support 4k BGP sessions with hold timers as low as 3 seconds on nonstop active routing (NSR) switchovers, depending on the number of BGP sessions. See the following table for timer details for the number of sessions.

BGP Hold-Timer Value (in seconds)	Number of BGP Sessions
3	80
5	120
10	200
15	400
30	600
45	800
90	1800

[See hold-time and precision-timers.]

BFD session damping for LACP interfaces (PTX10001-36MR, PTX10003, PTX10004, PTX10008, and PTX10016)—Starting in Junos OS Evolved Release 23.4R1, you can use BFD session damping on LACP interfaces to suppress BFD session state change notifications for a configured time period when thresholds for session flapping are exceeded. Session damping helps reduce potential instability from excessive BFD notifications.

Use the set bfd-liveness-detection damping configuration statement at the [edit dynamic-profiles name interfaces name aggregated-ether-option] hierarchy level to configure BFD session damping.

[See BFD Session Damping Overview.]

MC-LAG emulation in an EVPN deployment (ACX7024, ACX7100-32C, ACX7100-48C, ACX7348 and ACX7509)—Starting in Junos OS Evolved Release 23.4R1, you can emulate the function of an MC-LAG in active-standby mode in an EVPN configuration without having to configure an ICCP or ICL interface. In a standard EVPN configuration, logical interfaces configured on an aggregated Ethernet interface can have different designated forwarder (DF) election roles. To emulate an MC-LAG configuration, the designated forwarder takes on the role of the aggregated Ethernet interface. The provider edge (PE) device that is the non-DF device sends LACP unsynchronized packets to the CE device. This causes LACP to go down on the CE device, and the CE device does not use the links connected to the non-DF device for sending traffic.

To emulate MC-LAG functionality, enable the lacp-oos-on-ndf statement at the [edit interfaces interface name esi df-election-granularity per-esi] hierarchy level.

[See per-esi.]