326
C
HAPTER
34: OSPF C
ONFIGURATION
■
If the network type is broadcast or NBMA, ensure that there is at least one
interface with a priority greater than zero.
■
If an area is set to a stub area, ensure that the area is set to a stub area for all
the routers connected to this area.
■
Ensure that the interface types of two neighboring routers are consistent.
■
If two or more areas are configured, ensure that at least one area is configured
as the backbone area; that is, the area ID of an area is 0.
■
Ensure that the backbone area is connected to all the other areas.
■
Ensure that no virtual link passes through a stub area.
Global fault removal: If OSPF still cannot discover the remote routes after the
above procedure is performed, check the following configurations:
■
If two or more areas are configured on a router, at least one area should be
configured to be connected to the backbone area.
As shown in Figure 75, Router A and Router D are configured to belong to only
one area, whereas Router B (Area 0 and Area 1) and Router C (Area 1 and Area 2)
are configured to belong to two areas. Router B also belongs to area 0, which
meets the requirement. However, none of the areas of Router C is Area 0.
Therefore, a virtual link should be set up between Router C and Router B. Ensure
that Area 2 and Area 0 (backbone area) are interconnected.
Figure 75
OSPF area
■
A virtual link cannot pass through a stub area. The backbone area (Area 0)
cannot be configured as a stub area. So, if a virtual link has been set up
between RTB and RTC, neither Area 1 nor Area 0 can be configured as a stub
area. In Figure 75, only Area 2 can be configured as a stub area.
■
A router in a stub area cannot receive external routes.
■
The backbone area must guarantee the connectivity between various nodes.
Area 0
Area 1
Area 2
ABR
ABR
Transit Area
Virtual Link
Router A
Router B
Router C
Router D
Summary of Contents for Switch 7757
Page 32: ...32 CHAPTER 1 CLI OVERVIEW...
Page 70: ...70 CHAPTER 5 LOGGING IN USING MODEM...
Page 76: ...76 CHAPTER 7 LOGGING IN THROUGH NMS...
Page 86: ...86 CHAPTER 9 CONFIGURATION FILE MANAGEMENT...
Page 120: ...120 CHAPTER 13 ISOLATE USER VLAN CONFIGURATION...
Page 126: ...126 CHAPTER 14 SUPER VLAN...
Page 136: ...136 CHAPTER 16 IP PERFORMANCE CONFIGURATION...
Page 152: ...152 CHAPTER 17 IPX CONFIGURATION...
Page 164: ...164 CHAPTER 19 QINQ CONFIGURATION...
Page 172: ...172 CHAPTER 21 SHARED VLAN CONFIGURATION...
Page 182: ...182 CHAPTER 22 PORT BASIC CONFIGURATION...
Page 198: ...198 CHAPTER 24 PORT ISOLATION CONFIGURATION...
Page 208: ...208 CHAPTER 25 PORT SECURITY CONFIGURATION...
Page 224: ...224 CHAPTER 27 DLDP CONFIGURATION...
Page 232: ...232 CHAPTER 28 MAC ADDRESS TABLE MANAGEMENT...
Page 240: ...240 CHAPTER 29 CENTRALIZED MAC ADDRESS AUTHENTICATION CONFIGURATION...
Page 280: ...280 CHAPTER 30 MSTP CONFIGURATION...
Page 348: ...348 CHAPTER 35 IS IS CONFIGURATION...
Page 408: ...408 CHAPTER 39 802 1X CONFIGURATION...
Page 412: ...412 CHAPTER 40 HABP CONFIGURATION...
Page 422: ...422 CHAPTER 41 MULTICAST OVERVIEW...
Page 426: ...426 CHAPTER 42 GMRP CONFIGURATION...
Page 480: ...480 CHAPTER 47 PIM CONFIGURATION...
Page 506: ...506 CHAPTER 48 MSDP CONFIGURATION...
Page 552: ...552 CHAPTER 51 TRAFFIC ACCOUNTING CONFIGURATION...
Page 570: ...570 CHAPTER 53 HA CONFIGURATION...
Page 582: ...582 CHAPTER 54 ARP CONFIGURATION SwitchA arp protective down recover interval 200...
Page 622: ...622 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION...
Page 684: ...684 CHAPTER 61 QOS CONFIGURATION...
Page 718: ...718 CHAPTER 63 CLUSTER...
Page 738: ...738 CHAPTER 67 UDP HELPER CONFIGURATION...
Page 752: ...752 CHAPTER 69 RMON CONFIGURATION...
Page 772: ...772 CHAPTER 70 NTP CONFIGURATION...
Page 796: ...796 CHAPTER 72 FILE SYSTEM MANAGEMENT...
Page 802: ...802 CHAPTER 73 BIMS CONFIGURATION...
Page 814: ...814 CHAPTER 74 FTP AND TFTP CONFIGURATION...
Page 830: ...830 CHAPTER 75 INFORMATION CENTER...
Page 836: ...836 CHAPTER 76 DNS CONFIGURATION...
Page 852: ...852 CHAPTER 77 BOOTROM AND HOST SOFTWARE LOADING...
Page 858: ...858 CHAPTER 78 BASIC SYSTEM CONFIGURATION DEBUGGING...