Preference Values and Load Balancing

Load Balancing

Hierarchical concept

[edit]
user@Riesling# show

policy-options {
     policy-statement please-load-balance-traffic {
          then {
               load-balance per-packet;
          }
     }
}

Applied (and takes effect) to the router:

[edit routing-options]
user@Riesling# set forwarding-table export please-load-balance-traffic

user@Merlot> show route forwarding-table matching 192.168.80/24
Routing table:: inet
Internet:
Destination         Type    RtRef    Nexthop         Type     Index NhRef   Netif
192.168.80.1/32  user    0                                 ulst      30      14
                                                  10.222.10.0    ucst      20      19       so-0/0/0.0
                                                  10.20.20.0      ucst      26      22      so-0/0/3.0

Packets forwarded through Merlot toward Cabernet are sent across both next hops. The actual choice of a next hop is based on a microflow selection using the following Layer 3 criteria:

• Incoming interface
• Source IP address
• Destination IP address

We can enable additional criteria for the microflow selection of the forwarding table. These additional criteria are:

• Protocol (TCP or UDP)
• Source port number
• Destination port number

Defference:
1) The Internet Processor ASIC forwards packets across 8 equal-cost next hops.
The Internet Processor II ASIC, however, is able to forward across 16 equal-cost next hops.

2) The second difference between the two ASICs deals with the actual forwarding of user packets. The forwarding description described in this section is representative of the Internet Processor II
ASIC and is based on a microflow. This means that all user packets that match a certain set of  criteria will always follow the same path through the network. This assists end-user applications because it minimizes out-of-order packet delivery. The original Internet Processor ASIC forwards
packets on a per-packet basis only. Each individual data packet is sent in a round-robin fashion via a different interface.