This article is intended to supply information about the local-bias percentage on MC-LAG and LAG bundle interface as well as to determine if the same can be configurable as well as if there is a command to confirm the percentage on Juniper Networks switching platforms.

Customer needs to know local-bias percentage on MC-LAG and the command that can be run to confirm the same for an interface. The customer may have tested this on Juniper Networks MX Series routing platforms.

According to the below documentation Load Balancing, load balancing of network traffic between MC-LAG peers is 100 percent local bias. Load balancing of network traffic between multiple LAG members in a local MC-LAG node is achieved through a standard LAG hashing algorithm.

For more information on the hashing algorithm of LAG bundle load balancing, please visit the link Load Balancing and Ethernet Link Aggregation Overview

Upon testing local-bias configuration on QFX5210 in lab as well as on an MX960 routing platform. The observation is that the local-bias percentage can be configured on the MX960 but cannot be configured on the QFX5210. Based on the first document mentioned above, the local-bias is enabled by default with its default values for MG-LAG setups, although if you issue the command below in VTY on a switching platform such as EX Series QFX Series, you will see local-bias at 0%, because the percentage is not configurable on switching platforms, although it is configurable on MX Series routing platforms at hierarchy level [edit interfaces <interface-name> aggregated-ether-options load balancing local-bias]. The load balancing hierarchy does not exist on switching platforms.

Note that this is the only command that I was able to find to see the local-bias of an interface, and it is not an operational command nor a regular shell command. Also, the percentage will change only after configuring specific load balancing local-bias only applicable for MX Series routing platforms as explained above.

Checking local-bias in VTY:

First, you need to go shell mode with user root (user@switch> start shell user root), then you need to go VTY (user@switch% vty fpc#). At this point, you can run the command (FPC0(SWITCH vty)# show interface <LAG-interface>). See the example below:

user@switch:RE:0% vty fpc0

Switching platform (2200 Mhz Pentium processor, 639MB memory, 0KB flash)

FPC0(SWITCH vty)# show interface ae1

Physical device ae1 (Index 641, context 0x0) SNMP Index 563
 IPC sequence number initialized NO sequence number 0
 Administration interface
 Device flags: (0x0000000000000001) Present
 Flags: (0x0000000000008000) Up SNMP-Traps
JAM Capability: FALSE
 Capability Flags: Level 1 = 0x0000000000000020, Level 2 = 0x0000000000000000
 IFD Specific Flags: 0x0
 Interface redirects: Disabled
 Sparse DLCIs : Disabled
 Controller Interface: FALSE
 Locally managed: TRUE
 Shared Uplink: FALSE
 Transceiver channelized? FALSE
 SA multicast: FALSE
 MUP/MDOWN rcvd: TRUE
 Pad to minimum frame size: Disabled
 ifl count: 1
 Parent IFD:  641 ae1
LB Accounting: Off
Adaptive LB:
Tolerance: 20%
pps(1), bps(0) selection: 0
Flaps:
 Flap flag: Cleared, Marked ups: 2, Marked downs: 0
 Timed flag: Cleared, Down dtime: 0, Up dtime: 0
 Up/down timer: Stopped
 Append tstamp: 0+00:01:17.853, Yank tstamp: 0+00:01:17.860
Media:
 Type: Ethernet (3), Clocking: Internal (1), Link Flags: 0x0
 Encapsulation: Ethernet (1), Physical select: Unspecified (0)
 Up hold time: 0 ms, Down hold time: 0 ms
 Alternative hold time alg.: Disabled
 Speed: 200000 Mbps, MTU: 9192 bytes, Header: 14, Link select: 0
 CoS capability: flags:0x0000 hw max q: 0 usable max q: 10
 STS: 0 to 0 PDH: 0, Timeslot Mask: 0x00000000
 (ucode)Pop all label mode: 0
 Optimize for aggregate FRR: 0
 Share standby (vmx-only) : 0
 Dampening half life: 0
      max suppress 0
      reuse level 0
      suppress level 0
      enable 0
      suppress state 0
      priv flags 0
 Framing mode: Unspecified
 Load Balancing Flags: 0x0 Local-bias 0%
Unidirectional: Unspecified

Load Balancing

Load Balancing and Ethernet Link Aggregation Overview