Rate and give feedback:  Feedback Received. Thank You!

Rate and give feedback: 

X

This document helped resolve my issue

Yes No

Additional Comments

800 characters remaining

May we contact you if necessary?

Name:  

E-mail: 

Enter a valid Email ID

Need product assistance? Contact Juniper Support

Submit

This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply.

English  

English

Example: Configuring Multicast Load Balancing for Use with Aggregated 10-Gigabit Ethernet Interfaces on EX8200 Switches

EX8200 switches support multicast load balancing on link aggregation groups (LAGs). Multicast load balancing evenly distributes Layer 3 routed multicast traffic over the LAGs, You can aggregate up to twelve 10-gigabit Ethernet links to form a 120-gigabit virtual link or LAG. The MAC client can treat this virtual link as if it were a single link to increase bandwidth, provide graceful degradation as link failures occur, and increase availability. On EX8200 switches, multicast load balancing is enabled by default. However, if it is explicitly disabled, you can reenable it. .

Note: An interface with an already configured IP address cannot form part of the LAG.

Note: Only EX8200 standalone switches with 10-gigabit links support multicast load balancing. Virtual Chassis does not support multicast load balancing.

This example shows how to configure a LAG and reenable multicast load balancing:

Requirements

• Two EX8200 switches, one used as the access switch and one used as the distribution switch
• Junos OS Release 12.2 or later for EX Series switches

• Configure four 10-gigabit interfaces on the EX8200 distribution switch: xe-0/1/0, xe-1/1/0, xe-2/1/0, and xe-3/1/0. See Configuring Gigabit Ethernet Interfaces (CLI Procedure).

Overview and Topology

Multicast load balancing uses one of seven hashing algorithms to balance traffic between the individual 10-gigabit links in the LAG. For a description of the hashing algorithms, see multicast-loadbalance. The default hashing algorithm is crc-sgip. You can experiment with the different hashing algorithms until you determine the one that best balances your Layer 3 routed multicast traffic.

When a link larger than 10 gigabits is needed on an EX8200 switch, you can combine up to twelve 10-gigabit links to create more bandwidth. This example uses the link aggregation feature to combine four 10-gigabit links into a 40-gigabit link on the distribution switch. In addition, multicast load balancing is enabled to ensure even distribution of Layer 3 routed multicast traffic on the 40-gigabit link. In the sample topology illustrated in Figure 1, an EX8200 switch in the distribution layer is connected to an EX8200 switch in the access layer.

Note: Link speed is automatically determined based on the size of the LAG configured. For example, if a LAG is composed of four 10-gigabit links, the link speed is 40 gigabits per second).

Note: The default hashing algorithm, crc-sgip, involves a cyclic redundancy check of both the multicast packet source and group IP addresses.

Figure 1: 40-Gigabit LAG Composed of Four 10-Gigabit Links

You will configure a LAG on each switch and reenable multicast load balancing. When reenabled, multicast load balancing will automatically take effect on the LAG, and the speed is set to 10 gigabits per second for each link in the LAG. Link speed for the 40-gigabit LAG is automatically set to 40 gigabits per second.

Configuration

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Step-by-Step Procedure

1. Specify the number of aggregated Ethernet interfaces to be created:
   [edit chassis]
user@switch# set aggregated-devices ethernet device-count 1
2. Specify the minimum number of links for the aggregated Ethernet interface (aex), that is, the LAG, to be labeled up:

   Note: By default, only one link needs to be up for the LAG to be labeled up.

   [edit interfaces]
user@switch# set ae0 aggregated-ether-options minimum-links 1
3. Specify the four members to be included within the LAG:
   [edit interfaces]
user@switch# set xe-0/1/0 ether-options 802.3ad ae0
user@switch# set xe-1/1/0 ether-options 802.3ad ae0
user@switch# set xe-2/1/0 ether-options 802.3ad ae0
user@switch# set xe-3/1/0 ether-options 802.3ad ae0
4. Reenable multicast load balancing:
   [edit chassis]

   user@switch# set multicast-loadbalance

   Note: You do not need to set link speed the way you do for LAGs that do not use multicast load balancing. Link speed is automatically set to 40 gigabits per second on a 40-gigabit LAG.

5. You can optionally change the value of the hash-mode option in the multicast-loadbalance statement to try different algorithms until you find the one that best distributes your Layer 3 routed multicast traffic.

   If you change the hashing algorithm when multicast load balancing is disabled, the new algorithm takes effect after you reenable multicast load balancing.

Results

Check the results of the configuration:

user@switch>  show configuration
chassis

	aggregated-devices {
		ethernet {
		     device-count 1;
		}
	}
	multicast-loadbalance {
		hash-mode crc-gip; 
	}

interfaces
	xe-0/1/0 {
	ether-options {
			802.3ad ae0;
		}
	}
	xe-1/1/0 {
		ether-options {
			802.3ad ae0;
		}
	}
	xe-2/1/0 {
		ether-options {
			802.3ad ae0;
		}
	}
	xe-3/1/0 {
		ether-options {
			802.3ad ae0;
		}
	}
	ae0 {
		aggregated-ether-options {
			minimum-links 1;
		}
	}
}

Verification

To confirm that the configuration is working properly, perform these tasks:

• Verifying the Status of a LAG Interface
• Verifying Multicast Load Balancing

Verifying the Status of a LAG Interface

Purpose

Verify that a link aggregation group (LAG) (ae0) has been created on the switch.

Action

Verify that the ae0 LAG has been created:

Interface             Admin  	Link 	Proto      Local             Remote               

ae0                    up       up

ae0.0                  up       up     inet     10.10.10.2/24

 

Meaning

The interface name aex indicates that this is a LAG. A stands for aggregated, and E stands for Ethernet. The number differentiates the various LAGs.

Verifying Multicast Load Balancing

Purpose

Check that traffic is load-balanced equally across paths.

Action

Verify load balancing across the four interfaces:

Bytes=b, Clear=c, Delta=d, Packets=p, Quit=q or ESC, Rate=r, Up=^U, Down=^D
ibmoem02-re1                      Seconds: 3                   Time: 16:06:14

Interface    Link  Input packets        (pps)     Output packets        (pps)
 xe-0/1/0      Up        2058834         (10)          7345862         (19)
 xe-1/1/0      Up        2509289          (9)          6740592         (21)
 xe-2/1/0      Up        8625688         (90)         10558315         (20)
 xe-3/1/0      Up        2374154         (23)         71494375          (9)

Meaning

The interfaces should be carrying approximately the same amount of traffic.