EdgeRouter - Equal-Cost Multi Path (ECMP) Routing


EdgeOS supports Equal-Cost Multi Path (ECMP) routing. Assuming multiple routes exist for the same destination network, with same prefix and administrative distance, traffic will be balanced equally between the links.

Applicable to the latest EdgeOS firmware on all EdgeRouter models. Please see the Related Articles below for more information.

ECMP Routing Example

The following example shows a default route ( configured with two next-hop addresses. The EdgeRouter balances between the two routes in a round-robin fashion when using the EdgeOS v1.7.0 firmware and higher. On the v1.6.0 firmware version and lower the router balances the traffic in a flow-hash manner.

CLI: Access the Command Line Interface (CLI). You can do this using the CLI button in the GUI or by using a program such as PuTTY.

Verify the routing table output with the show ip route command:

show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF,
I - ISIS, B - BGP, > - selected route, * - FIB route

S>* via, eth0
* via, eth1

The show ip route summary command will show the ECMP statistics.

show ip route summary 
IP routing table name is Default-IP-Routing-Table(0)
IP routing table maximum-paths   : 8
Total number of IPv4 routes      : 20
Total number of IPv4 paths       : 24
Route Source    Networks
connected       12
static          8
Total           20
FIB             0
ECMP statistics (active in ASIC):
Total number of IPv4 ECMP routes : 4
Total number of IPv4 ECMP paths    : 8
Number of routes with 2 ECMP paths : 4

Related Articles

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