HP 5500 Ei 5500 Si Switch Series Configuration Guide
Have a look at the manual HP 5500 Ei 5500 Si Switch Series Configuration Guide online for free. It’s possible to download the document as PDF or print. UserManuals.tech offer 1114 HP manuals and user’s guides for free. Share the user manual or guide on Facebook, Twitter or Google+.
![Page 765
76
NOTE:
Virtual links cannot transit totally stub areas.
Configuring an NSSA area
A stub area cannot redistribute routes. Configur e the area as an NSSA area to allow for route
redistribution by keeping other stub area characteristics.
To configure an NSSA area:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id
router-id | vpn-instance
vpn-instance-name ] * N/A
3.
Enter area view.
area area-id
N/A
4....](http://img.usermanuals.tech/thumb/36/58909/w64_hp-5500-ei-5500-si-switch-series-configuration-guide-764.png "Page 765
76
NOTE:
Virtual links cannot transit totally stub areas.
Configuring an NSSA area
A stub area cannot redistribute routes. Configur e the area as an NSSA area to allow for route
redistribution by keeping other stub area characteristics.
To configure an NSSA area:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id
router-id | vpn-instance
vpn-instance-name ] * N/A
3.
Enter area view.
area area-id
N/A
4....")
![Page 766
77
Step Command Remarks
4. Configure a virtual link. vlink-peer
router-id [ hello seconds
| retransmit seconds | trans-delay
seconds | dead seconds | simple
[ plain | cipher ] password | { md5
| hmac-md5 } key-id [ plain |
cipher ] password ] * You must configure this command on
both ends of a virtual link.
hello
and dead intervals must be
identical on both ends of the virtual
link.
Configuring OSPF network types
OSPF classifies networks into the foll owing types by...](http://img.usermanuals.tech/thumb/36/58909/w64_hp-5500-ei-5500-si-switch-series-configuration-guide-765.png "Page 766
77
Step Command Remarks
4. Configure a virtual link. vlink-peer
router-id [ hello seconds
| retransmit seconds | trans-delay
seconds | dead seconds | simple
[ plain | cipher ] password | { md5
| hmac-md5 } key-id [ plain |
cipher ] password ] * You must configure this command on
both ends of a virtual link.
hello
and dead intervals must be
identical on both ends of the virtual
link.
Configuring OSPF network types
OSPF classifies networks into the foll owing types by...")
72 BFD Bidirectional forwarding detection (BFD) provides a single mechanism to quickly detect and monitor the connectivity of links between OSPF neighbors, reducing network convergence time. For more information about BFD, see High Availability Configuration Guide . Protocols and standards • RFC 1765, OSPF Database Overflow • RFC 2328, OSPF Version 2 • RFC 3101, OSPF Not-So-Stubby Area (NSSA) Option • RFC 3137, OSPF Stub Router Advertisement • RFC 3630, Traffic Engineering Extensions to OSPF Version 2 • RFC 481 1, OSPF Out-of-Band LSDB Resynchronization • R F C 4 812 , OSPF Restart Signaling • RFC 4813, OSPF Link-Local Signaling OSPF configuration task list Make a proper plan before configuring OSPF. To ru n OS P F i n a ro u t i n g d o m a i n, yo u m u s t fi r s t e n a b l e OS P F o n t h e ro u t e rs. Th e n us e t h e d e fa u l t s e t t i n g s of parameters such as the hello interval, LSA delay timer, and SPF calculation interval. You can also configure them as needed. OSPF routers should be configured on an area basis. Wrong configurations may cause communication failures, routing information blocks, and routing loops. Complete the following tasks to configure OSPF: Task Remarks Enabling OSPF Required Configuring OSPF areas Configuring a stub area Optional Configuring an NSSA area Configuring a virtual link Configuring OSPF network types Configuring the OSPF network type for an interface as broadc ast Optional Configuring the OSPF network type for an interface as NBMA Optional Configuring the OSPF network type for an interface as P2MP Optional Configuring the OSPF network type for an interface as P2P Optional Configuring OSPF route control Configuring OSPF route summarization Optional Configuring OSPF inbound route filtering Optional Configuring ABR Type-3 LSA filtering Optional Configuring an OSPF cost for an interface Optional Configuring the maximum number of OSPF routes Optional Configuring the maximum number of ECMP routes Optional
73 Task Remarks Configuring OSPF preference Optional Configuring OSPF route redistribution Optional Tuning and optimizing OSPF networks Configuring OSPF packet timers Optional Specifying LSA transmission delay Optional Specifying SPF calculation interval Optional Specifying the LSA arrival interval Optional Specifying the LSA generation interval Optional Disabling interfaces from receiving and sending OSPF packets Optional Configuring stub routers Optional Configuring OSPF authentication Optional Adding the interface MTU into DD packets Optional Configuring the maximum number of external LSAs in LSDB Optional Enabling compatibility with RFC 1583 Optional Logging neighbor state changes Optional Configuring OSPF network management Optional Enabling message logging Optional Enabling the advertisement and reception of opaque LSAs Optional Configuring OSPF to give priority to receiving and processing hello packets Optional Configuring the LSU transmit rate Optional Setting the DSCP value for OSPF packets Optional Enabling OSPF ISPF Optional Configuring OSPF FRR Optional Configuring OSPF Graceful Restart Configuring the OSPF GR Restarter Optional Configuring the OSPF GR Helper Optional Triggering OSPF Graceful Restart Optional Configuring BFD for OSPF Optional Enabling OSPF You must enable OSPF before performing other OSPF configuration tasks. Configuration prerequisites Configure the link layer protocol, and IP addresses for interfaces so that neighboring nodes can reach each other.
74 Configuration procedure To enable OSPF on a router, create an OSPF process and specify areas with which the process is associated, and the network segments contained in each area. If an interface’s IP address resides on a network segment of an area, the interface belongs to the area and is enabled with OSPF, and OSPF advertises the direct route of the interface. To run OSPF, a router must have a router ID, which is the unique identifier of the router in the AS. Following is additional information about router IDs: • You can specify a router ID when creating the OSPF process. Any two routers in an AS must have different router IDs. In practice, the ID of a ro uter is the IP address of one of its interfaces. • If you specify no router ID when creating the OS PF process, the global router ID is used. HP recommends you to specify a router ID when you create the OSPF process. OSPF can run multiple processes and supports VPNs as follows: • When a router runs multiple OSPF processes, specify a router ID for each process, which takes effect locally and has no influence on packet exchange between routers. Two routers having different process IDs can exchange packets. • OSPF support for VPNs enables an OSPF process to run in a specified VPN. To enable OSPF: Step Command Remarks 1. Enter system view. system-view N/A 2. Configure a global router ID. router id router-id Optional. Not configured by default. If no global router ID is configured, the highest loopback interface IP address, if any, is used as the router ID. If no loopback interface IP address is available, the highest physical interface IP address is used, regardless of the interface status. 3. Enable an OSPF process and enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * Not enabled by default. 4. Configure a description for the OSPF process. description description Optional. Not configured by default. 5. Configure an OSPF area and enter OSPF area view. area area-id Not configured by default. 6. Configure a description for the area. description description Optional. Not configured by default. 7. Specify a network to enable OSPF on the interface attached to the network. network ip-address wildcard-mask Not configured by default. A network segment can only belong to one area.
75 Configuring OSPF areas After splitting an OSPF AS into multiple areas, configure some areas as stub areas or NSSA areas as needed. If no connection can be achieved between the backbone and a non-backbone area, or within the backbone itself, you can configure virtual links to solve it. Configuration prerequisites Before you configure an OSPF area, complete the following tasks: • Configure IP addresses for interfaces, and make sure that all neighboring nodes can reach each other at the network layer. • Configure OSPF basic functions. Configuring a stub area Configure a non-backbone area at the AS edge as a stub area by configuring the stub command on all the routers attached to the area. In this way, Type-5 LSAs will not be flooded within the stub area, reducing the routing table size. The ABR generates a default route into the stub area so all packets destined outside of the AS are sent through the default route. To further reduce the routing table size and routing information exchanged in the stub area, configure it as a totally stub area by using the stub [ no-summary ] command on the ABR. In this way, neither AS external routes nor inter-area routing information will be distributed into the area. All the packets destined outside of the AS or area will be sent to the ABR for forwarding. To configure OSPF areas: Step Command Remarks 1. Enter system view. system-view N/A 2. Enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * N/A 3. Enter area view. area area-id N/A 4. Configure the area as a stub area. stub [ default-route-advertise-always | no-summary ] * Not configured by default. You must use the stub command on routers attached to a stub area. The backbone area cannot be a totally stub area. A (totally) stub area cannot have an ASBR because AS external routes cannot be distributed into the stub area. 5. Specify a cost for the default route advertised to the stub area. default-cost cost Optional. 1 by default. The default-cost command takes effect only on the ABR of a stub area.
76 NOTE: Virtual links cannot transit totally stub areas. Configuring an NSSA area A stub area cannot redistribute routes. Configur e the area as an NSSA area to allow for route redistribution by keeping other stub area characteristics. To configure an NSSA area: Step Command Remarks 1. Enter system view. system-view N/A 2. Enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * N/A 3. Enter area view. area area-id N/A 4. Configure the area as an NSSA area. nssa [ default-route-advertise | no-import-route | no-summary | translate-always | translator-stability-interval value ] * Not configured by default. You must use the nssa command on all the routers attached to an NSSA area. 5. Specify a cost for the default route advertised to the NSSA area. default-cost cost Optional. 1 by default. The default-cost command is available only on the ABR/ASBR of an NSSA area. Configuring a virtual link Non-backbone areas exchange rout ing information via the backbone area. Connectivity between the backbone and non-backbone areas and within the backbone must be maintained. If the required physical links are not available for this connectivity maintenance, you can configure virtual links to resolve it. To configure a virtual link: Step Command Remarks 1. Enter system view. system-view N/A 2. Enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * N/A 3. Enter area view. area area-id N/A
77
Step Command Remarks
4. Configure a virtual link. vlink-peer
router-id [ hello seconds
| retransmit seconds | trans-delay
seconds | dead seconds | simple
[ plain | cipher ] password | { md5
| hmac-md5 } key-id [ plain |
cipher ] password ] * You must configure this command on
both ends of a virtual link.
hello
and dead intervals must be
identical on both ends of the virtual
link.
Configuring OSPF network types
OSPF classifies networks into the foll owing types by the link layer protocol:
• Broadcast —When the link layer protocol is Ethernet or FDDI, OSPF considers the network type as
broadcast by default.
• NBMA —When the link layer protocol is Frame Relay, ATM, or X.25, OSPF considers the network
type as NBMA by default.
• P2P—When the link layer protocol is PPP, LAPB, or HDLC, OSPF considers the network type as P2P
by default.
The following are examples of how you can change the network type of an interface as needed:
• When an NBMA network becomes fully meshed through address mapping—any two routers in the
network have a direct virtual circuit in between, you can change the network type to broadcast to
avoid manual configuration of neighbors.
• When some routers in the broadcast network do not support multicast, you can change the network
type to NBMA.
• A n N B M A n e t wo r k m u s t b e f u l l y m e s h e d. I f i t i s p a r t i a l l y m e s h e d, yo u c a n c h a n g e t h e n e t wo r k t yp e
to P2MP to simplify configuration and save network costs.
• If a router on an NBMA network has only one neighbor, you can change the network type to P2P
to save network costs.
If two interfaces on a link are both configured as the broadcast, NBMA, or P2MP network type, they
cannot establish a neighbor relationship unless they are on the same network segment.
Configuration prerequisites
Before you configure OSPF network types, complete the following tasks:
• Configure IP addresses for interfaces, making neighboring nodes accessible with each other at
network layer.
• Configure OSPF basic functions.
Configuring the OSPF network type for an interface as
broadcast
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter interface view. interface
interface-type
interface-number N/A
78 Step Command Remarks 3. Configure the OSPF network type for the interface as broadcast. ospf network-type broadcast By default, the network type of an interface depends on the link layer protocol. 4. Configure a router priority for the interface. ospf dr-priority priority Optional. The default router priority is 1. Configuring the OSPF network ty pe for an interface as NBMA After configuring the network type of an interface as NBMA, you must make some special configurations. Because NBMA interfaces cannot find neighbors via broadcasting hello packets, you must specify neighbors and their router priorities. (A router priority of 0 means the router does not have the DR election right. A router priority greater than 0 means the router has the DR election right.) The router priority configured with the ospf dr-priority command is for actual DR election. The priority configured with the peer command indicates whether a neighbor has the election right or not. If you configure the router priority for a neighbor as 0, the local router will assume the neighbor has no election ri g h t, a n d t hu s s e n d n o h e l l o p a cke t s t o t h i s n ei g h b o r. H oweve r, i f t h e l o c a l ro u t e r i s t h e D R o r B D R, i t s t i l l sends hello packets to the neighbor with priority 0 for neighborship establishment. To configure the OSPF network type for an Interface as NBMA: Step Command Remarks 1. Enter system view. system-view N/A 2. Enter interface view. interface interface-type interface-number N/A 3. Configure the OSPF network type for the interface as NBMA. ospf network-type nbma By default, the network type of an interface depends on the link layer protocol. 4. Configure a router priority for the interface. ospf dr-priority priority Optional. The default router priority is 1. 5. Exit to system view. quit N/A 6. Enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * N/A 7. Specify a neighbor and its router priority. peer ip-address [ cost value | dr-priority dr-priority ] N/A Configuring the OSPF network type for an interface as P2MP Step Command Remarks 1. Enter system view. system-view N/A
79 Step Command Remarks 2. Enter interface view. interface interface-type interface-number N/A 3. Configure the OSPF network type for the interface as P2MP. ospf network-type p2mp [ unicast ] By default, the network type of an interface depends on the link layer protocol. After you configure the OSPF network type for an interface as P2MP unicast, all packets are unicast over the interface. The interface cannot broadcast hello packets to discover neighbors. In that case, you need to manually specify the neighbors. 4. Exit to system view. quit N/A 5. Enter OSPF view. ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * N/A 6. Specify a neighbor and its router priority on a P2MP unicast network. peer ip-address [ cost value | dr-priority dr-priority ] Required if the interface type is P2MP unicast. Configuring the OSPF network type for an interface as P2P Step Command Remarks 1. Enter system view. system-view N/A 2. Enter interface view. interface interface-type interface-number N/A 3. Configure the OSPF network type for the interface as P2P. ospf network-type p2p By default, the network type of an interface depends on the link layer protocol. Configuring OSPF route control This section describes how to control the advertisement and reception of OSPF routing information, as well as route redistribution from other protocols. Configuration prerequisites Before you configure OSPF route control, complete the following tasks: • Configure IP addresses for interfaces. • Configure OSPF basic functions. • Configure filters if routing information filtering is needed.
80
Configuring OSPF route summarization
Ro u t e s u m m a riza t io n i s wh e n a n A B R o r AS B R s u m m a rize s ro u te s wi t h t h e s a m e p re fix i n t o a s i n g l e ro u t e
and distributes it to other areas.
Route summarization reduces the traffic of routing information exchanged between areas and the sizes
of routing tables on routers, improving route calculation speed on routers.
For example, there are three internal routes in an area: 19.1.1.0/24, 19.1.2.0/24, and 19.1.3.0/24. By
configuring route summarization on the ABR, the three routes are summarized into the route 19.1.0.0/16
that is advertised to other areas.
Configuring route summarization on an ABR
If contiguous network segments are available in the area, you can summarize them into a single network
segment. An ABR generates Type-3 LSAs on a per network segment basis for an attached non-backbone
area.
The ABR in the area distributes only the summary LSA to reduce the scale of LSDBs on routers in other
areas and the influence of topology changes.
To configure route summarization on an ABR:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id router-id
| vpn-instance vpn-instance-name ] * N/A
3. Enter OSPF area view.
area area-id N/A
4. Configure ABR route
summarization. abr-summary
ip-address { mask |
mask-length } [ advertise |
not-advertise ] [ cost cost ]
Not configured by default.
The command is available on an
ABR only.
Configuring route summarization when redistributing routes into OSPF on an ASBR
Without route summarization, an ASBR advertises each
redistributed route in a separate ASE LSA. After
a summary route is configured, the ASBR advertises only the summary route in an ASE LSA instead of
more specific routes, which reduces the number of LSAs in the LSDB.
The ASBR summarizes redistributed Type-5 LSAs that fall into the specified address range. If the ASBR is
in an NSSA area, it also summarizes Type-7 LSAs that fall into the specified address range. If the ASBR
is also the ABR, it summarizes Type-5 LSAs translated from Type-7 LSAs.
To configure route summarization when redistributing routes into OSPF on an ASBR:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id router-id
| vpn-instance vpn-instance-name ]* N/A
3.
Configure ASBR route
summarization. asbr-summary
ip-address { mask |
mask-length } [ tag tag | not-advertise
| cost cost ] *
The command is available on an
ASBR only.
Not configured by default.
81
Configuring OSPF inbound route filtering
O S P F c a l cu l a t e s ro u t e s by u s i n g L SA s . T h e c a l c u l a t e d routes can be filtered and only permitted routes are
installed into the OSPF routing table.
OSPF provides the following filtering methods:
• Filters routing information by destination address through ACLs and IP address prefixes
• Filters routing information by next hop through the filtering criteria configured with the gateway
keyword
• Filters routing information by destination address through ACLs and IP address prefixes and by next
hop through the filtering criteria configured with the gateway keyword
• Filters routing information by routing policy specified by the route-policy keyword
For more information about IP prefix list and routing policy, see Configuring routing policies.
T
o configure inbound route filtering:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id router-id |
vpn-instance vpn-instance-name ] * N/A
3.
Configure inbound
route filtering. filter-policy {
acl-number [ gateway
ip-prefix-name ] | gateway ip-prefix-name |
ip-prefix ip-prefix-name [ gateway
ip-prefix-name ] | route-policy
route-policy-name } import
Not configured by default.
Configuring ABR Type-3 LSA filtering
You can configure an ABR to filter Type-3 LSAs advertised to an area.
To configure Type-3 LSA filtering on an ABR:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter OSPF view. ospf
[ process-id | router-id router-id |
vpn-instance vpn-instance-name ] * N/A
3.
Enter area view.
area area-id N/A
4. Configure ABR Type-3 LSA
filtering. filter { acl-number
| ip-prefix
ip-prefix-name } { import | export } Not configured by
default.
Configuring an OSPF cost for an interface
You can configure an OSPF cost for an interface by using either of the following methods:
•
Configure the cost value in interface view.
• Configure a bandwidth reference value for the interface. OSPF computes the cost with this formula:
Interface OSPF cost = Bandwidth reference value (100 Mbps)/Interface bandwidth (Mbps). If the