HP GbE2c HP GbE2c Ethernet Blade Switch for c-Class BladeSystem Application Gu - Page 115

Host routes for load balancing, ABR Load Sharing, ABR Failover, Equal Cost Multipath ECMP

Page 115 highlights

3. Enable OSPF authentication for Area 2 on switch 4. >> # /cfg/l3/ospf/aindex 2/auth password 4. Configure a simple text password up to eight characters for the virtual link between Area 2 and Area 0 on switches 2 and 4. >> # /cfg/l3/ospf/virt 1/key packard Use the following commands to configure MD5 authentication on the switches shown in the figure: 2. Enable OSPF MD5 authentication for Area 0 on switches 1, 2, and 3 >> # /cfg/l3/ospf/aindex 0/auth md5 5. Configure MD5 key ID for Area 0 on switches 1, 2, and 3. >> # /cfg/l3/ospf/md5key 1/key test 6. Assign MD5 key ID to OSPF interfaces on switches 1, 2, and 3. >> # /cfg/l3/ospf/if 1 >> OSPF Interface 1 # mdkey 1 >> OSPF Interface 1 # ../if 2 >> OSPF Interface 2 # mdkey 1 >> OSPF Interface 1 # ../if 3 >> OSPF Interface 3 # mdkey 1 7. Enable OSPF MD5 authentication for Area 2 on switch 4. >> # /cfg/l3/ospf/aindex 2/auth md5 8. Configure MD5 key for the virtual link between Area 2 and Area 0 on switches 2 and 4. >> # /cfg/l3/ospf/md5key 2/key packard 9. Assign MD5 key ID to OSPF virtual link on switches 2 and 4. >> # /cfg/l3/ospf/virt 1/mdkey 2 Host routes for load balancing GbE2c software implementation of OSPF includes host routes. Host routes are used for advertising network device IP addresses to external networks, accomplishing the following goals: • ABR Load Sharing As a form of load balancing, host routes can be used for dividing OSPF traffic among multiple ABRs. To accomplish this, each switch provides identical services but advertises a host route for a different IP address to the external network. If each IP address serves a different and equal portion of the external world, incoming traffic from the upstream router should be split evenly among ABRs. • ABR Failover Complementing ABR load sharing, identical host routes can be configured on each ABR. These host routes can be given different costs so that a different ABR is selected as the preferred route for each server and the others are available as backups for failover purposes. • Equal Cost Multipath (ECMP) With equal cost multipath, a router potentially has several available next hops towards any given destination. ECMP allows separate routes to be calculated for each IP Type of Service. All paths of equal cost to a given destination are calculated, and the next hops for all equal-cost paths are inserted into the routing table. If redundant routes via multiple routing processes (such as OSPF, RIP, BGP, or static routes) exist on your network, the switch defaults to the OSPF-derived route. OSPF 115

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OSPF 115
3.
Enable OSPF authentication for Area 2 on switch 4.
>> # /cfg/l3/ospf/aindex 2/auth password
4.
Configure a simple text password up to eight characters for the virtual link between Area 2 and Area 0 on
switches 2 and 4.
>> # /cfg/l3/ospf/virt 1/key packard
Use the following commands to configure MD5 authentication on the switches shown in the figure:
2.
Enable OSPF MD5 authentication for Area 0 on switches 1, 2, and 3
>> # /cfg/l3/ospf/aindex 0/auth md5
5.
Configure MD5 key ID for Area 0 on switches 1, 2, and 3.
>> # /cfg/l3/ospf/md5key 1/key test
6.
Assign MD5 key ID to OSPF interfaces on switches 1, 2, and 3.
>> # /cfg/l3/ospf/if 1
>> OSPF Interface 1 # mdkey 1
>> OSPF Interface 1 # ../if 2
>> OSPF Interface 2 # mdkey 1
>> OSPF Interface 1 # ../if 3
>> OSPF Interface 3 # mdkey 1
7.
Enable OSPF MD5 authentication for Area 2 on switch 4.
>> # /cfg/l3/ospf/aindex 2/auth md5
8.
Configure MD5 key for the virtual link between Area 2 and Area 0 on switches 2 and 4.
>> # /cfg/l3/ospf/md5key 2/key packard
9.
Assign MD5 key ID to OSPF virtual link on switches 2 and 4.
>> # /cfg/l3/ospf/virt 1/mdkey 2
Host routes for load balancing
GbE2c software implementation of OSPF includes host routes. Host routes are used for advertising network device IP
addresses to external networks, accomplishing the following goals:
ABR Load Sharing
As a form of load balancing, host routes can be used for dividing OSPF traffic among multiple ABRs. To
accomplish this, each switch provides identical services but advertises a host route for a different IP address to
the external network. If each IP address serves a different and equal portion of the external world, incoming
traffic from the upstream router should be split evenly among ABRs.
ABR Failover
Complementing ABR load sharing, identical host routes can be configured on each ABR. These host routes can
be given different costs so that a different ABR is selected as the preferred route for each server and the others
are available as backups for failover purposes.
Equal Cost Multipath (ECMP)
With equal cost multipath, a router potentially has several available next hops towards any given destination.
ECMP allows separate routes to be calculated for each IP Type of Service. All paths of equal cost to a given
destination are calculated, and the next hops for all equal-cost paths are inserted into the routing table.
If redundant routes via multiple routing processes (such as OSPF, RIP, BGP, or static routes) exist on your network, the
switch defaults to the OSPF-derived route.