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- About aimarchitect
08-18-2017
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11-21-2011
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Created by
aimarchitect
in Switching
in Switching
07-12-2012
11:16 AM
07-12-2012
11:16 AM
Hi Giuseppe, Sorry about not including the point of the Virtual Link in the original post. I was trying to simplify to the example. I was wrong to think it was not relevant. I have now read the "Understanding OSPF Transit Capability" link above and found that it does indeed describe the behaviour we see in the network. Especially, this part of the article describes it perfectly: "What’s really interesting, is that an intra-area route actually takes the INTER-area path! The transit capability essentially allows the use of non-backbone inter-area routes to optimize inter-area paths and area 0 intra-area paths IF the area in question is transit!" So this question is answered. If you see routing between Area 0 prefixes going through Non-0 Areas, and being listed in the routing table as "O" and "intra area" it may be confusing, but it is not wrong. This is the work of OSPF Transit Capability.
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Created by
aimarchitect
in Switching
in Switching
07-12-2012
10:15 AM
07-12-2012
10:15 AM
Here is an update. With the help of Cisco TAC we are on the road to understanding how the Area 0 loopback of C2 routes to the Area 0 loopback of S2 across Area 14 and calls it "intra area". Something not pictured in the original diagram is that S2 has a Virtual Link to a router in Area 14. Still need verification, but it seems that the existence of this Virtual Link, coupled with the default "on" state for "capability transit" allows the above noted condition to occur. Here are a couple of links (one provided by Cisco TAC) that I am looking at now with relation to this: http://blog.ine.com/2009/09/14/understanding-ospf-transit-capability/ http://ieoc.com/forums/t/4807.aspx
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Created by
aimarchitect
in Switching
in Switching
07-08-2012
03:56 PM
07-08-2012
03:56 PM
Hi Soroush, I have finally seen the light. I wasn't thinking properly. I was thinking too generally. I was thinking in terms of routers ("lab_A can get to lab_Z"), but it really only makes sense to think in terms of networks. Basic stuff. Just because "lab_A" (actually 52.1.0.2) can ping the router-id 100.0.0.1 on lab_Z when the link between lab_A and lab_2 is down doesn't help connectivity to Area 0 for anything on lab_A except its network configured in Area 52 (52.1.0.0/24). Imagine all the routers in this network running BGP and peering to the loopback/router-id addresses. Peering would be lost between lab_A and lab_Z (when the link between A and 2 goes down) even though a simple ping from lab_A to lab_Z works. Great, the virtual-link is needed after all. I feel better now. I guess this is a good reminder for not to using simple pings to verify network functionality. Thanks again, Greg
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Created by
aimarchitect
in Switching
in Switching
07-08-2012
02:05 PM
07-08-2012
02:05 PM
Thanks Soroush, the review was helpful. Regarding number 3 from your list. The router-id is the loopback, but there is also a network statement for that IP in Area 19. That is why I did not think lab_A could become an Area 52 internal router and get to the core that way. It seems that configuring the router-id in an area with a network statement does restrict the router to that area. This is the insight I think the data is showing me that I had not known before.
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Created by
aimarchitect
in Switching
in Switching
07-08-2012
12:19 PM
07-08-2012
12:19 PM
Soroush and J., Thanks for the responses. I was under the impression that, even though lab_A has interfaces configured in Area 52 and Area 19, the fact that it has its router-id configured in Area 19 was most important, so it couldn't just become a member of Area 52. The data seems to show otherwise. OK, so there exists a class, "Non-0 Multi Area Router"? This router can reach Area 0 through any area it has an interface configured in, even though none of them are Area 0? I see that since router lab_A has no interface configured in Area 0, it can not perform the ABR function for other Area 19 routers (lab_aa) to get to Area 0 until a Virtual-Link to 0 is configured (between lab_A and lab_B). Thanks
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Created by
aimarchitect
in Switching
in Switching
07-06-2012
08:46 PM
07-06-2012
08:46 PM
Hi, I need some help understanding OSPF behaviour in a mini-lab I set up with GNS3. I am seeing a router that is a member of two areas (but not one of them being area 0) use an area (52) different than the area configured for its router-id (19) to reach area 0 when the connection through its own area to area 0 is shut down. Doesn't a Virtual-Link need to be configured for this transit to happen? Or is it just other routers connected to this router that require the Virtual-Link? I've attached a GNS3 topology and all the configs. I have also included some testing output below. The scenarion is testing connectivity from area 19 routers lab_aa and lab_A to area 0 router lab_Z when the connection between lab_A and lab_2 is shut down. I expect that if the link between lab_A and lab_2 is shut down then lab_aa would lose connectivity to area 0 and therefore lab_Z. I am getting this expected result. Here is test data for lab_aa: L-A-B--aa#sh ip route 100.0.0.1 % Network not in table L-A-B--aa#sh ip ospf dat sum 100.0.0.1 OSPF Router with ID (19.19.19.1) (Process ID 65525) Summary Net Link States (Area 19) LS age: 1036 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(Network) Link State ID: 100.0.0.1 (summary Network Number) Advertising Router: 100.0.0.100 LS Seq Number: 80000004 Checksum: 0x9277 Length: 28 Network Mask: /32 TOS: 0 Metric: 2 L-A-B--aa# L-A-B--aa#ping 100.0.0.100 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 100.0.0.100, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) L-A-B--aa# What I was not expecting was for lab_A to be able to tranist Area 52 to Area 0 without a Virtual-Link configured between it and lab_B. With the link between lab_A and lab_2 shutdown, this test data shows lab_A has connectivity to area 0 router lab_Z. L-A-B--A#ping 100.0.0.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 100.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/66/88 ms L-A-B--A#trace 100.0.0.1 Type escape sequence to abort. Tracing the route to 100.0.0.1 1 52.1.0.1 48 msec 16 msec 24 msec 2 52.2.0.2 44 msec 40 msec 44 msec 3 100.1.0.1 68 msec * 64 msec L-A-B--A#sh ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 19.0.0.0/8 is variably subnetted, 6 subnets, 2 masks C 19.19.19.19/32 is directly connected, Loopback0 O IA 19.3.0.0/24 [110/3] via 52.1.0.1, 00:15:35, FastEthernet1/0 O IA 19.19.19.2/32 [110/4] via 52.1.0.1, 00:15:35, FastEthernet1/0 O IA 19.2.0.0/24 [110/4] via 52.1.0.1, 00:15:35, FastEthernet1/0 O 19.19.19.1/32 [110/2] via 19.1.0.1, 00:15:35, FastEthernet0/0 C 19.1.0.0/24 is directly connected, FastEthernet0/0 100.0.0.0/8 is variably subnetted, 3 subnets, 2 masks O IA 100.0.0.100/32 [110/3] via 52.1.0.1, 00:15:36, FastEthernet1/0 O IA 100.1.0.0/24 [110/3] via 52.1.0.1, 00:15:36, FastEthernet1/0 O IA 100.0.0.1/32 [110/4] via 52.1.0.1, 00:15:36, FastEthernet1/0 52.0.0.0/8 is variably subnetted, 3 subnets, 2 masks O 52.52.52.52/32 [110/2] via 52.1.0.1, 01:03:44, FastEthernet1/0 C 52.1.0.0/24 is directly connected, FastEthernet1/0 O 52.2.0.0/24 [110/2] via 52.1.0.1, 01:03:46, FastEthernet1/0 L-A-B--A# L-A-B--A#sion Neighbor ID Pri State Dead Time Address Interface 19.19.19.1 1 FULL/BDR 00:00:33 19.1.0.1 FastEthernet0/0 52.52.52.52 1 FULL/DR 00:00:37 52.1.0.1 FastEthernet1/0 L-A-B--A#sioib Interface PID Area IP Address/Mask Cost State Nbrs F/C Lo0 65525 19 19.19.19.19/32 1 LOOP 0/0 Fa0/0 65525 19 19.1.0.2/24 1 DR 1/1 Fa2/0 65525 19 19.2.0.2/24 1 DOWN 0/0 Fa1/0 65525 52 52.1.0.2/24 1 BDR 1/1 L-A-B--A#siib Interface IP-Address OK? Method Status Protocol FastEthernet0/0 19.1.0.2 YES manual up up FastEthernet1/0 52.1.0.2 YES manual up up FastEthernet2/0 19.2.0.2 YES manual administratively down down FastEthernet3/0 unassigned YES unset administratively down down Loopback0 19.19.19.19 YES manual up up L-A-B--A#
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Created by
aimarchitect
in Switching
in Switching
06-06-2012
02:59 PM
06-06-2012
02:59 PM
Hi Giusepe, This is tough issue and we are about to open a TAC case with the intention of getting an OSPF developer. You are saying: ...the route on C2 is derived from LSA type 4 in area 14 originated by S2 and referring to S2 router-id 10.180.20.6. The route destination (S2 router-id 10.180.20.6) is in Area 0, so how can an Area 14 link (VLAN 14) ever be considered Intra Area for Area 0? An Intra Area, Area 0 path should never leave Area 0, right? I don't see a Type 4 LSA in Area 14 originated by S2 and referring to S2 router-id 10.180.20.6 Are these the right commands to run on S2 to look for it? S2#sh ip ospf dat asbr-summary 10.180.20.6 OSPF Router with ID (10.180.20.6) (Process ID 65525) Summary ASB Link States (Area 0) LS age: 1989 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: 10.180.20.4 LS Seq Number: 8000117A Checksum: 0xA65A Length: 28 Network Mask: /0 TOS: 0 Metric: 1 LS age: 1 (DoNotAge) Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted, not 10.180.20.6] LS Seq Number: 800007B7 Checksum: 0x5661 Length: 28 Network Mask: /0 TOS: 0 Metric: 10 LS age: 186 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted, not 10.180.20.6] LS Seq Number: 8000002E Checksum: 0x96A5 Length: 28 Network Mask: /0 TOS: 0 Metric: 16 Summary ASB Link States (Area 14) Adv Router is not-reachable LS age: 475 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: 10.180.20.4 LS Seq Number: 80003152 Checksum: 0xBE46 Length: 28 Network Mask: /0 TOS: 0 Metric: 5 Adv Router is not-reachable LS age: 583 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted, not 10.180.20.6] LS Seq Number: 80001178 Checksum: 0xB636 Length: 28 Network Mask: /0 TOS: 0 Metric: 10 Adv Router is not-reachable LS age: 963 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted, not 10.180.20.6] LS Seq Number: 8000314B Checksum: 0x6493 Length: 28 Network Mask: /0 TOS: 0 Metric: 6 S2#sh ip ospf dat asbr-summary self-originate OSPF Router with ID (10.180.20.6) (Process ID 65525) Summary ASB Link States (Area 0) LS age: 1469 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.4 (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80001177 Checksum: 0xB44F Length: 28 Network Mask: /0 TOS: 0 Metric: 1 LS age: 1469 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80001177 Checksum: 0x50A9 Length: 28 Network Mask: /0 TOS: 0 Metric: 1 ... Summary ASB Link States (Area 14) LS age: 1998 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80003150 Checksum: 0xE821 Length: 28 Network Mask: /0 TOS: 0 Metric: 5 LS age: 1998 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80003150 Checksum: 0xDE2A Length: 28 Network Mask: /0 TOS: 0 Metric: 5 LS age: 476 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 8000319A Checksum: 0x229E Length: 28 Network Mask: /0 TOS: 0 Metric: 2 LS age: 1 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.4 (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80003151 Checksum: 0xC83D Length: 28 Network Mask: /0 TOS: 0 Metric: 5 LS age: 3 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 8000866B Checksum: 0x6237 Length: 28 Network Mask: /0 TOS: 0 Metric: 1 LS age: 4 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: [output omitted, not 10.180.20.6] (AS Boundary Router address) Advertising Router: 10.180.20.6 LS Seq Number: 80003151 Checksum: 0x8C73 Length: 28 Network Mask: /0 TOS: 0 Metric: 5 ...
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Created by
aimarchitect
in Switching
in Switching
05-31-2012
05:53 PM
05-31-2012
05:53 PM
Hi Giuseppe, You are right, I see that a Type 1 LSA for S2 router-id 10.180.20.6 is not present in the Area 14 database on C2. And yes, a Type 4 LSA for S2 router-id 10.180.20.6 is presnt in the Area 0 and Area 14 databases on C2 (see show ip ospf datbase command output below). Do I understand correctly that C2 takes the Type 4 LSA from the Area 14 database for 10.180.20.6 to make this routing table entry? C2#sh ip route 10.180.20.6 Routing entry for 10.180.20.6/32 Known via "ospf 65525", distance 110, metric 2, type intra area Last update from 10.180.21.22 on Vlan14, 02:09:58 ago Routing Descriptor Blocks: * 10.180.21.22, from 10.180.20.6, 02:09:58 ago, via Vlan14 Route metric is 2, traffic share count is 1 C2#sh ip ospf dat router 10.180.20.6 OSPF Router with ID (10.180.20.4) (Process ID 65525) Router Link States (Area 0) Routing Bit Set on this LSA LS age: 318 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.180.20.6 Advertising Router: 10.180.20.6 LS Seq Number: 800085FA Checksum: 0xC6BA Length: 108 Area Border Router AS Boundary Router Number of Links: 7 Link connected to: a Virtual Link (Link ID) Neighboring Router ID: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Stub Network (Link ID) Network/subnet number: [output omitted] (Link Data) Network Mask: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Stub Network (Link ID) Network/subnet number: [output omitted] (Link Data) Network Mask: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Transit Network (Link ID) Designated Router address: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Stub Network (Link ID) Network/subnet number: 10.180.20.6 (Link Data) Network Mask: 255.255.255.255 Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Transit Network (Link ID) Designated Router address: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 5 Link connected to: a Transit Network (Link ID) Designated Router address: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 5 Router Link States (Area 14) Routing Bit Set on this LSA LS age: 317 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.180.20.6 Advertising Router: 10.180.20.6 LS Seq Number: 800085A0 Checksum: 0x539 Length: 72 Area Border Router AS Boundary Router Virtual Link Endpoint Number of Links: 4 Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 250 Link connected to: a Stub Network (Link ID) Network/subnet number: [output omitted] (Link Data) Network Mask: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 250 Link connected to: a Stub Network (Link ID) Network/subnet number: [output omitted] (Link Data) Network Mask: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 Link connected to: a Transit Network (Link ID) Designated Router address: [output omitted] (Link Data) Router Interface address: [output omitted] Number of TOS metrics: 0 TOS 0 Metrics: 1 C2#sh ip ospf dat asbr-summary 10.180.20.6 OSPF Router with ID (10.180.20.4) (Process ID 65525) Summary ASB Link States (Area 0) LS age: 909 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: 10.180.20.4 LS Seq Number: 8000107D Checksum: 0xA35B Length: 28 Network Mask: /0 TOS: 0 Metric: 1 LS age: 3 (DoNotAge) Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted] LS Seq Number: 800007B7 Checksum: 0x5661 Length: 28 Network Mask: /0 TOS: 0 Metric: 10 LS age: 382 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted] LS Seq Number: 80000063 Checksum: 0x2CDA Length: 28 Network Mask: /0 TOS: 0 Metric: 16 Summary ASB Link States (Area 14) LS age: 156 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: 10.180.20.4 LS Seq Number: 80003055 Checksum: 0xBB47 Length: 28 Network Mask: /0 TOS: 0 Metric: 5 Adv Router is not-reachable LS age: 572 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted] LS Seq Number: 8000107B Checksum: 0xB337 Length: 28 Network Mask: /0 TOS: 0 Metric: 10 Adv Router is not-reachable LS age: 883 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 10.180.20.6 (AS Boundary Router address) Advertising Router: [output omitted] LS Seq Number: 8000304E Checksum: 0x6194 Length: 28 Network Mask: /0 TOS: 0 Metric: 6 C2#
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Created by
aimarchitect
in Switching
in Switching
05-27-2012
11:31 PM
05-27-2012
11:31 PM
Giuseppe, Thank you for taking the time to read my post. I'm glad you understand the problem...the route from C2 to the loopback router-id address 10.180.20.6 on S2 should not be intra-area via 10.180.21.22 in Area 14 (VLAN 14). Instead it should be intra-area via 10.180.16.6 in Area 0 (VLAN 10). Exactly what process and data does C2 use to make its deciscions about classifying routes as intra-area or inter-area? Here is the output of some show commands run on routers C2 and S2: C2#sh ip ospf nei Neighbor ID Pri State Dead Time Address Interface 10.180.20.6 1 2WAY/DROTHER 964 msec 10.180.16.6 Vlan10 10.180.20.6 254 FULL/BDR 00:00:30 10.180.21.22 Vlan14 [output omitted] C2#sh ip ospf database adv-router 10.180.20.6 OSPF Router with ID (10.180.20.4) (Process ID 65525) Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 10.180.20.6 10.180.20.6 1392 0x80008555 0x001215 7 Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Summary Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Summary ASB Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Router Link States (Area 14) Link ID ADV Router Age Seq# Checksum Link count 10.180.20.6 10.180.20.6 1514 0x800084FB 0x005192 4 Summary Net Link States (Area 14) Link ID ADV Router Age Seq# Checksum 10.180.20.6 10.180.20.6 1758 0x800084C8 0x00B18C [output omitted] Summary ASB Link States (Area 14) Link ID ADV Router Age Seq# Checksum [output omitted] Type-5 AS External Link States Link ID ADV Router Age Seq# Checksum Tag [output omitted] C2# C2#sh ip ospf int brie Interface PID Area IP Address/Mask Cost State Nbrs F/C Vl10 65525 0 10.180.16.4/23 5 DROTH 2/9 Vl14 65525 14 10.180.21.17/28 1 DR 6/6 [output omitted] C2#sh run | s ospf router ospf 65525 router-id 10.180.20.4 log-adjacency-changes area 0 authentication message-digest area 14 authentication message-digest redistribute static subnets network 10.180.20.4 0.0.0.0 area 0 network 10.180.16.0 0.0.1.255 area 0 network 10.180.21.16 0.0.0.15 area 14 [output omitted] C2#sh ip proto *** IP Routing is NSF aware *** Routing Protocol is "ospf 65525" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 10.180.20.4 It is an area border and autonomous system boundary router Redistributing External Routes from, static, includes subnets in redistribution Number of areas in this router is 2. 2 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: [output omitted] 10.180.16.0 0.0.1.255 area 0 10.180.20.4 0.0.0.0 area 0 10.180.21.16 0.0.0.15 area 14 Passive Interface(s): [output omitted] Routing Information Sources: Gateway Distance Last Update 10.180.20.6 110 02:01:25 [output omitted] S2#sh ip ospf nei Neighbor ID Pri State Dead Time Address Interface 10.180.20.4 1 2WAY/DROTHER 872 msec 10.180.16.4 Vlan10 10.180.20.4 255 FULL/DR 00:00:38 10.180.21.17 Vlan14 [output omitted] S2#sh ip ospf database adv-router 10.180.20.4 OSPF Router with ID (10.180.20.6) (Process ID 65525) Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 10.180.20.4 10.180.20.4 19 0x8000DE41 0x007EFA 13 Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Summary Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Summary ASB Link States (Area 0) Link ID ADV Router Age Seq# Checksum [output omitted] Router Link States (Area 14) Link ID ADV Router Age Seq# Checksum Link count 10.180.20.4 10.180.20.4 60 0x8000B133 0x00C010 2 Net Link States (Area 14) Link ID ADV Router Age Seq# Checksum [output omitted] Summary Net Link States (Area 14) Link ID ADV Router Age Seq# Checksum 10.180.20.4 10.180.20.4 60 0x8000B121 0x009923 Summary ASB Link States (Area 14) Link ID ADV Router Age Seq# Checksum [output omitted] Type-5 AS External Link States Link ID ADV Router Age Seq# Checksum Tag [output omitted] S2# S2#sh ip ospf int brie Interface PID Area IP Address/Mask Cost State Nbrs F/C Vl10 65525 0 10.180.16.6/23 5 DROTH 2/9 Vl14 65525 14 10.180.21.22/28 1 BDR 6/6 [output omitted] S2#sh run | s ospf router ospf 65525 router-id 10.180.20.6 log-adjacency-changes area 0 authentication message-digest area 14 authentication message-digest redistribute static subnets network 10.180.20.6 0.0.0.0 area 0 network 10.180.16.0 0.0.1.255 area 0 network 10.180.21.16 0.0.0.15 area 14 [output omitted] S2#sh ip proto *** IP Routing is NSF aware *** Routing Protocol is "ospf 65525" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 10.180.20.6 It is an area border and autonomous system boundary router Redistributing External Routes from, static, includes subnets in redistribution Number of areas in this router is 2. 2 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: [output omitted] 10.180.16.0 0.0.1.255 area 0 10.180.20.6 0.0.0.0 area 0 10.180.21.16 0.0.0.15 area 14 Passive Interface(s): [output omitted] Routing Information Sources: Gateway Distance Last Update [output omitted] 10.180.20.4 110 01:59:35
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Created by
aimarchitect
in Switching
in Switching
05-25-2012
05:19 PM
05-25-2012
05:19 PM
I would like to dscuss how an OSPF router might insert an intra area "O" OSPF route into the routing table when it seems that the route should have been an inter-area "IA O" route and therfore [due to precedence of O before IA O, regardless of cost] lost to a higher cost intra area "O" route. The attached diagram helps illustrate the question. Take note of the two ABR routers, C2 and S2. C2 and S2 each have an interface in Area 14. 10.180.21.0/24 is configured in Area 14. The router interface addresses in this network/Area are .17 and .22 respectively. The OSPF cost on these interfaces is 1. C2 and S2 also each have an interface in Area 0. 10.180.16.0/24 is configured in Area 0. The router interface addresses in this network/Area are .4 and .6 respectively. The OSPF cost on these interfaces is 5. C2 and S2 are also configured with router-ids 10.180.20.4 and 10.180.20.6 respectively. These host addresses are configured in Area 0 on each router. Which interface should C2 use reach 10.180.20.6 (S2 router-id) and why? Running a "show ip route | i 10.180.20.6" command on C2 does (but should not?) show this: C2#sh ip route | i 10.180.20.6 O 10.180.20.6/32 [110/2] via 10.180.21.22, 1d08h, Vlan14 How can a route from C2 to 10.180.20.6 (S2) with the next hop 10.180.21.22 be considered an "O" if it is not going through Area 0? How exactly can C2 know/classify the route to 10.180.20.6 (S2) via 10.180.21.22 as an "O" instead of an "IA O"? Thanks for any responses...
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03-29-2012
10:59 AM
I found EoMPLS (not port mode) supported on the 3745 platform with IOS c3745-spservicesk9-mz.124-15.T14.bin Here is output from virtual router in GNS3 showing the fact: Router(config-if)#xconnect ? A.B.C.D IP address of peer Router(config-if)#xconnect 1.1.1.1 99 ? encapsulation Data encapsulation method pw-class Pseudowire-class to use for encapsulation and protocol configuration Router(config-if)#xconnect 1.1.1.1 99 enc Router(config-if)#xconnect 1.1.1.1 99 encapsulation ? l2tpv3 Use L2TPv3 encapsulation mpls Use MPLS encapsulation Router(config-if)#xconnect 1.1.1.1 99 encapsulation mp Router(config-if)#xconnect 1.1.1.1 99 encapsulation mpls ? pw-class Optional pseudowire-class to use for advanced configuration Router(config-if)#xconnect 1.1.1.1 99 encapsulation mpls Router(config-if-xconn)#? Xconnect configuration commands: backup Xconnect backup configuration commands default Set a command to its defaults exit Exit from Xconnect submode configuration no Negate a command or set its defaults Router(config-if-xconn)#end Router#sh ver Cisco IOS Software, 3700 Software (C3745-SPSERVICESK9-M), Version 12.4(15)T14, RELEASE SOFTWARE (fc2) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2010 by Cisco Systems, Inc. Compiled Tue 17-Aug-10 12:56 by prod_rel_team ROM: ROMMON Emulation Microcode ROM: 3700 Software (C3745-SPSERVICESK9-M), Version 12.4(15)T14, RELEASE SOFTWARE (fc2) Router uptime is 4 minutes System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19 System image file is "t ftp://255.255.255.255/unknown " This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to com *Mar 1 00:04:21.283: %SYS-5-CONFIG_I: Configured from console by consoleply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately. A summary of U.S. laws governing Cisco cryptographic products may be found at: http://www.cisco.com/wwl/export/crypto/tool/stqrg.html If you require further assistance please contact us by sending email to export@cisco.com . Cisco 3745 (R7000) processor (revision 2.0) with 249856K/12288K bytes of memory. Processor board ID FTX0945W0MY R7000 CPU at 350MHz, Implementation 39, Rev 2.1, 256KB L2, 512KB L3 Cache 18 FastEthernet interfaces DRAM configuration is 64 bits wide with parity enabled. 151K bytes of NVRAM. 16384K bytes of ATA System CompactFlash (Read/Write) Configuration register is 0x2142 Router#
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03-29-2012
10:31 AM
Hi, I noticed in this post: https://supportforums.cisco.com/thread/2100502 the author reports using EoMPLS feature on a 3725 platform with the interface command something like this: "xconnect 1.1.1.1 99 encapsulation mpls". The Cisco feature navigator does not include the 3725 platform in this feature. I do notice that the feature is included on the 2801C platform. Is there a silicon or hardware difference between an 2801 and a 2801C router? Can anyone report running EoMPLS on their standard 2801 router? Many Thanks! Greg
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12-21-2011
10:43 AM
During configuration it looks like this: policy-map QOS-POLICY-INTERFACE-MAP service-policy VOIP-PRIORITY-MAP class class-default shape average 2400000 ..must be configured like this instead: policy-map QOS-POLICY-INTERFACE-MAP class class-default shape average 2400000 service-policy VOIP-PRIORITY-MAP
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12-21-2011
09:41 AM
There is something (maybe obviously) wrong with the above configuration. I will not be able to use the access-lists I wanted to use to match the traffic for the classes. First, it is not allowed to match access-lists (at least it wasn't on the ASA5505 8.2(5) I was using), and second the access-lists would never get hit on the outside interface because the traffic is all encapsulated in the IPSec packets. So the client needs to install DSCP marking capable LAN switches. Until that time we will prioritized VoIP traffic, since we know it is DSCP EF marked. We will take a position of prioritizing 20% of total bandwidth since it approximates the needs pretty well. With 3000000bps total bandwidth at SD, 20% prioritization means 600000bps. This translates into prioritizing about 15 calls using 40000bps for each call (codec being used is G729). Here is the config: priority-queue outside class-map SD-CV-VOIP-CLASS match tunnel-group 2.2.2.2 match dscp ef class-map SD-ST-VOIP-CLASS match tunnel-group 3.3.3.3 match dscp ef class-map SD-OC-VOIP-CLASS match tunnel-group 4.4.4.4 match dscp ef policy-map VOIP-PRIORITY-MAP class SD-CV-VOIP-CLASS priority class SD-ST-VOIP-CLASS priority class SD-OC-VOIP-CLASS priority policy-map QOS-POLICY-INTERFACE-MAP service-policy VOIP-PRIORITY-MAP class class-default shape average 2400000 service-policy QOS-POLICY-INTERFACE-MAP interface outside Comments? Ideas? Suggestions? Thanks
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12-15-2011
11:06 AM
SD has 16 VoIP phones in active use. I want to guarantee each phone 64000bps, meaning 1024000bps guaranteed(prioritized) for VoIP traffic. With the remainder of bandwidth at SD (3000000-1024000) 1976000bps, I want to shape near as possible to 32% for Filemaker traffic, 8% for Crashplan traffic, and 60% for other/web. Is this config valid? Will it suit my needs? ip access-list extended OUTBOUND-FILEMAKER-TRAFFIC-ACL permit tcp host 192.168.0.9 any eq 5033 ip access-list extended OUTBOUND-CRASHPLAN-TRAFFIC-ACL permit tcp host 192.168.0.9 any eq 4242 ip access-list extended SD-CV-VOIP-ACL permit ip host 192.168.0.7 host 192.168.1.7 ip access-list extended SD-ST-VOIP-ACL permit ip host 192.168.0.7 host 192.168.2.7 ip access-list extended SD-OC-VOIP-ACL permit ip host 192.168.0.7 host 192.168.3.7 priority-queue outside class-map SD-CV-VOIP-CLASS match tunnel-group 2.2.2.2 match dscp ef (or match access-list SD-CV-VOIP-ACL) class-map SD-ST-VOIP-CLASS match tunnel-group 3.3.3.3 match dscp ef (or match access-list SD-ST-VOIP-ACL) class-map SD-OC-VOIP-CLASS match tunnel-group 4.4.4.4 match dscp ef (or match access-list SD-OC-VOIP-ACL) class-map FILEMAKER-CLASS match access-list OUTBOUND-FILEMAKER-TRAFFIC-ACL class-map CRASHPLAN-CLASS match access-list OUTBOUND-CRASHPLAN-TRAFFIC-ACL policy-map VOIP-PRIORITY-MAP class SD-CV-VOIP-CLASS priority class SD-ST-VOIP-CLASS priority class SD-OC-VOIP-CLASS priority policy-map INTERFACE-TOTAL-POLICY-MAP service-policy VOIP-PRIORITY-MAP class FILEMAKER-CLASS shape average 632000 class CRASHPLAN-CLASS shape average 152000 class class-default shape average 1184000 service-policy INTERFACE-TOTAL-POLICY-MAP interface outside
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Created by
aimarchitect
in Switching
07-12-2012
07-12-2012
Hi Giuseppe,Sorry about not including the point of the Virtual Link in
the original post. I was tryi...
Created by
aimarchitect
in Switching
07-12-2012
07-12-2012
Here is an update. With the help of Cisco TAC we are on the road to
understanding how the Area 0 loo...
Created by
aimarchitect
in Switching
07-08-2012
07-08-2012
Hi Soroush,I have finally seen the light. I wasn't thinking properly. I
was thinking too generally. ...
Created by
aimarchitect
in Switching
07-08-2012
07-08-2012
Thanks Soroush, the review was helpful.Regarding number 3 from your
list. The router-id is the loopb...
Created by
aimarchitect
in Switching
07-08-2012
07-08-2012
Soroush and J., Thanks for the responses. I was under the impression
that, even though lab_A has int...
Created by
aimarchitect
in Switching
07-06-2012
07-06-2012
Hi,I need some help understanding OSPF behaviour in a mini-lab I set up
with GNS3. I am seeing a rou...
Created by
aimarchitect
in Switching
06-06-2012
06-06-2012
Hi Giusepe,This is tough issue and we are about to open a TAC case with
the intention of getting an ...
Created by
aimarchitect
in Switching
05-31-2012
05-31-2012
Hi Giuseppe,You are right, I see that a Type 1 LSA for S2 router-id
10.180.20.6 is not present in th...
Created by
aimarchitect
in Switching
05-27-2012
05-27-2012
Giuseppe,Thank you for taking the time to read my post. I'm glad you
understand the problem...the ro...
Created by
aimarchitect
in Switching
05-25-2012
05-25-2012
I would like to dscuss how an OSPF router might insert an intra area "O"
OSPF route into the routing...
03-29-2012
I found EoMPLS (not port mode) supported on the 3745 platform with IOS
c3745-spservicesk9-mz.124-15....
03-29-2012
Hi,I noticed in this post:
https://supportforums.cisco.com/thread/2100502 the author reports using
E...
12-21-2011
During configuration it looks like this:policy-map
QOS-POLICY-INTERFACE-MAP service-policy VOIP-PRIO...
12-21-2011
There is something (maybe obviously) wrong with the above configuration.
I will not be able to use t...
Public Statistics
| Date Registered | 11-21-2011 03:15 PM |
| Date Last Visited | 08-18-2017 03:53 AM |
| Total Messages Posted | 24 |
| Total Helpful Votes Received | 10 |
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