FTOS Configuration Guide for the C-Series - Force10 Networks

Hash algorithm
The load-balance command discussed above selects the hash criteria applied to port channels. In addition,
you can fine-tune the hashing algorithm that is applied with the hash-algorithm command.
For the E-Series, you can select one of 47 possible hash algorithms (16 on EtherScale):
Command Syntax Command Mode Purpose
[no] hash-algorithm
{algorithm-number} | {ecmp
number} {lag number} {linecard
number ip-sa-mask value
ip-da-mask value}
On C-Series and S-Series, the hash-algorithm command is specific to ECMP groups and has different
defaults from the E-Series. The default ECMP hash configuration is crc-lower. This takes the lower 32 bits
of the hash key to compute the egress port. Other options for ECMP hash-algorithms are:
• crc-upper — uses the upper 32 bits of the hash key to compute the egress port
• dest-ip — uses destination IP address as part of the hash key
• lsb — always uses the least significant bit of the hash key to compute the egress port
To change to another method, use the following command in the CONFIGURATION mode:
Command Syntax Command Mode Purpose
hash-algorithm ecmp {crc-upper} |
{dest-ip} | {lsb}
For more on load-balancing, see “Equal Cost Multipath and Link Aggregation Frequently Asked
Questions” in the E-Series FAQ section of iSupport:
https://www.force10networks.com/CSPortal20/KnowledgeBase/ToolTips.aspx
VLAN Interfaces and Layer 3
CONFIGURATION Change the default (0) to another algorithm and
apply it to ECMP, LAG hashing, or a particular
line card.
For details on the algorithm choices, see the
command details in the IP Routing chapter of the
FTOS Command Reference.
CONFIGURATION Change to another algorithm.
VLANs are logical interfaces and are, by default, in Layer 2 mode. Physical interfaces and port channels
can be members of VLANs. For more information on VLANs and Layer 2, refer to Chapter 9, Layer 2, on
page 181. See also Chapter 11, VLAN Stacking, on page 227.
Note: To monitor VLAN interfaces, use the Management Information Base for Network Management of
TCP/IP-based internets: MIB-II (RFC 1213). Monitoring VLAN interfaces via SNMP is supported only on
E-Series.
FTOS supports Inter-VLAN routing (Layer 3 routing in VLANs). You can add IP addresses to VLANs and
use them in routing protocols in the same manner that physical interfaces are used. For more information
on configuring different routing protocols, refer to the chapters on the specific protocol.
266 Interfaces