Fs S5500-48t8sp 48-port Gigabit Ethernet Switches User Guide

FS S5500-48T8SP 48-Port Gigabit Ethernet Switches
User Guide

Chapter 1 OSPFv3 Configuration

1.1 Overview
OSPFv3 is an IGP routing protocol developed by the OSPF working group of IETF for the IPv6 network. OSPFv3 supports the IPv6 subnet, the mark of the external  routing information and the packet’s authentication.
OSPFv3 and OSPFv2 have a lot in common:

• Both router ID and area ID are 32 bit.
• The following are the same type of packets: Hello packets, DD packets, LSR packets, LSU packets and LSAck packets.
• Having the same neighbor discovery mechanism and the same neighborhood generation mechanism
• Having the same LSA expansion mechanism and the same LSA aging mechanism

The main differences of both OSPFv3 and OSPFv2 are shown below:

• OSPFv3 is running on the basis of link, while OSPFv2 is running on the basis of network segment.
• OSPFv3can run multiple instances on the same link.
• OSPFv3 labels its neighbor through router ID, while OSPFv2 labels its neighbor through IP.
• OSPFv3 defines 7 classes of LSAs.
  The following table shows some key functions in the realization of the OSPFv3 functions.

1.2 OSPFv3 Configuration Task List
OSPFv3 demands the switchover of routing data between in-domain router, ABR and ASBR. In order to simplify the settings, you can make related configuration to enable them to work under the default parameters without any authentication; if you want to change some parameters, you must guarantee that the parameters on all routers are identical.
To set OSPFv3, you must perform the following tasks. Except that the task of activating OSPFv3 is mandatory, other settings are optional.

• Enabling OSPFv3
• Setting the parameters of the OSPFv3 interface
• Setting OSPFv3 on different physical networks
• Setting the parameters of the OSPFv3 domain
• Configuring the NSSA Domain of OSPFv3
• Setting the Route Summary in the OSPFv3 Domain
• Setting the Summary of the Forwarded Routes
• Generating a Default Route
• Choosing the route ID on the loopback interface
• Setting the management distance of OSPFv3
• Setting the Timer of Routing Algorithm
• Monitoring and Maintaining OSPFv3

1.3 OSPFv3 Configuration Tasks
1.3.1 Enabling OSPFv3
Before OSPFv3 is enabled, the function to forward the IPv6 packets must be enabled.
Run the following commands in global configuration mode:

Run the following command in interface configuration mode:

Note: If the OSPFv3 process is still not created before OSPFv3 is enabled on an
interface, the OSPFv3 process will be automatically created.

1.3.2 Setting the Parameters of the OSPFv3 Interface
During OSPFv3 realization, related OSPFv3 parameters on an interface are allowed to be modified according to actual requirements. Of cause you have no need to change every parameter, but you have to make sure that some parameters are consistent on all routers in the connected networks.
Run the following commands in interface configuration mode to do relevant configurations:

1.3.5 Setting the Parameters of the OSPFv3 Domain
The configurable domain parameters include: authentication, designating a stub area and specifying a weight for a default summary route. Its authentication is based on password protection.
The stub area means that external routes cannot be distributed to this area. Instead, ABR generates a default external route that enters the stub area, enabling the stub area to  communicate with external networks of an autonomous area. In order to make use of the attributes supported by the OSPF stub, the default route must be used in the stub  area. To further reduce LSAs that are forwarded to the stub area, you can forbid the summary function on ABR.
Run the following command in router configuration mode to set the domain’s parameters:

As to those areas that are not backbone areas and do not connect the backbone areas directly or as to those discontinuous areas, the OSPFv3 virtual link can be used to establish a logic connectivity. In order to create a virtual link, you have to perform configuration at the two terminals of the virtual link. If only one terminal is configured, the virtual link cannot work.
Run the following command in router configuration mode to set the domain’s parameters:

As to those areas that are not backbone areas and do not connect the backbone areas directly or as to those discontinuous areas, the OSPFv3 virtual link can be used to establish a logic connectivity. In order to create a virtual link, you have to perform configuration at the two terminals of the virtual link. If only one terminal is configured, the virtual link cannot work.
Run the following command in router configuration mode to set the domain’s parameters:

1.3.6 Setting the Route Summary in the OSPFv3 Domain
With this function ABR can broadcast a summary route to other areas. In OSPFv3 ABR will broadcast each network to other areas. If network IDs are distributed to be continuous, you can set ABR to broadcast a summary route to other areas. The summary route can cover all networks in a certain range.
Run the following command in router configuration mode to set the address’ range:

1.3.7 Setting the Summary of the Forwarded Routes
When routes are distributed from other routing areas to the OSPFv3 routing area, each route is singularly broadcasted as an external LSA. However, you can set a route on a router to make this route cover an address range. In this way, the size of the OSPFv3 link-state database can be reduced.
Run the following command in router configuration mode to set a summary route:

1.3.8 Generating a Default Route
ASBR should generate a default route to enter the OSPFv3 routing area. Whenever it is, you make configuration to enable a router to distribute a route to the OSPFv3 routing area and this route becomes ASBR automatically. However, ASBR does not generate a default route by default to enter the OSPFv3 routing area.

1.3.9 Choosing the Route ID on the Loopback Interface
OSPFv3 uses the maximum IPv4 address as its router ID. If the interface that connects the IPv4 address is down or the IPv4 address is deleted, the OSPF process will
recalculate the ID of this new router and retransmit the routing information from all interfaces.
If an IPv4 address is configured on a loopback interface, the router will first use the IPv4 address of loopback as its ID. Because the loopback interface will never be down, the routing table is greatly stable.
The router can first select the loopback interface as its ID or select the maximum IPv4 address in all loopback interfaces as its ID. If there is no loopback interface, the IPv4 address of a router will be used as the router ID. You cannot specify OSPFv3 to use any specific interface.
Run the following commands in global configuration mode to set the IP loopback interface:

1.3.10 Setting the Management Distance of OSPFv3
The management distance means the trust level of the routing information source.
Generally speaking, the management distance is an integer between 0 and 255. The bigger its value is, the lower the trust level is. If the management distance is 255, the  routing information source will be distrusted and omitted.
OSPFv3 uses three different kinds of management distances: inter-domain, inner-domain and exterior. The routes in a domain are called inner-domain routes; the routes to  other domains are called inter-domain routes; the routes transmitted from other routing protocols are called the exterior routes. The default value of each kind of routes is  110.

1.3.11 Setting the Timer of Routing Algorithm
You can set the delay between receiving the topology change information and calculating SPF. You can also set the interval between two continuous SFP algorithm.
Run the following command in router configuration mode:

1.3.12 Monitoring and Maintaining OSPFv3
The network statistics information which can be displayed includes the content of the
IP routing table, caching and database. This kind of information can help users to judge the usage of network resources and solve network problems.
You can run the following commands to display all kinds of routing statistics information:

1.4 OSPFv3 Configuration Example
1.4.1 Example for OSPFv3 Route Learning Settings
OSPFv3 requires switching information among many internal routers, ABR and ASBR.
In the minimum settings, the OSPFv3-based router works under the case that all its parameters take their default values and there is no authentication.
The following are three configuration examples:
The first example shows the commands for basic OSPFv3 settings.
The second example shows multiple OSPFv3 processes can be set on a router.
The third example shows how to use OSPFv3 to learn routes.
The fourth example shows how to set the OSPFv3 virtual link.

1. Basic OSPFv3 Configuration Example
   The following example shows a simple OSPFv3 settings. In this example, you have to activate process 90, connect Ethernet interface 0 to area 0.0.0.0, distribute RIPng  to OSPFv3 and OSPFv3 to RIPng.
   ipv6 unicast-routing
   ! interface vlan 10
   ipv6 address 2001::1/64
   ipv6 enable
   ipv6 rip aaa enable
   ipv6 rip aaa split-horizon
   ipv6 ospf 90 area 0
   ipv6 ospf cost 1
   ! router ospfv3 90
   router-id 1.1.1.1
   redistribute rip
   ! router ripng aaa
   redistribute ospf 90
2. Configuring multiple OSPFv3 processes
   The following example shows that two OSPFv3 processes are created.
   ipv6 unicast-routing
   ! interface vlan 10
   ipv6 address 2001::1/64
   ipv6 enable
   ipv6 ospf 109 area 0 instance 1
   ipv6 ospf 110 area 0 instance 2
   ! interface vlan 11
   ip address 2002::1/64
   ipv6 enable
   ipv6 ospf 109 area 1 instance 1
   ipv6 ospf 110 area 1 instance 2
   router ospfv3 109
   router-id 1.1.1.1
   redistribute static
   ! router ospfv3 110
   router-id 2.2.2.2
   Each interface can belong to many OSPFv3 processes, but if an interface belongs to multiple OSPFv3 processes each OSPFv3 process must correspond to different instances.
3. Complicated configuration example
   The following example shows how to configure multiple routers in a single OSPFv3 autonomous system. The following figure shows the network topology of the configuration example:
   Configure the router according to the above-mentioned figure:
   R1：
   interface vlan 0
   ipv6 enable
   ipv6 ospf 1 area 1
   ! interface vlan 1
   ipv6 enable
   ipv6 ospf 1 area 0
   ! ipv6 route 2001::/64 6::2
   ! router ospfv3 1
   router-id 1.1.1.1
   redistribute static
4. Configuring the virtual link
   The following example shows how to configure a virtual link in a single autonomous OSPFv3 system. The following figure shows the network topology of the  configuration example:
   Configure the router according to the above-mentioned figure:
   R1：
   interface vlan 0
   ipv6 address 101::1/64
   ipv6 enable
   ipv6 ospf 1 area 1
   ! interface vlan 1
   ipv6 address 6::1/64
   ipv6 enable
   ipv6 ospf 1 area 0
   ! ipv6 route 2001::/64 6::2
   ! router ospfv3 1
   router-id 200.200.200.1
   area 1 virtual-link 200.200.200.2
   redistribute static
   ! R2：
   interface vlan 0
   ipv6 address 101::2/64
   ipv6 enable
   ipv6 ospf 1 area 1
   ! interface vlan 1
   ipv6 address 888::8/64
   ipv6 enable
   ipv6 ospf 1 area 2
   ! router ospfv3 1
   router-id 200.200.200.2
   area 1 virtual-link 200.200.200.1
   ! Browsing the state of the OSPFv3 neighbor:
   R1#show ipv6 ospf neighbor
   OSPFv3 Process (1)
   Neighbor ID Pri State
   Dead Time Interface Instance ID
   200.200.200.2
   1 Full/DR
   00:00:35 VLAN0
   0 200.200.200.2
   1 Full/ – 00:00:36 VLINK1 0

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References

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