Questions tagged [ospf]
For questions about OSPF. Open Shortest Path First (OSPF) is a link-state routing protocol for Internet Protocol (IP) networks.
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0answers
42 views
OSPF over IPIP tunnel doesn't work for CSR 1000v in AWS
I literally have the following topology shown in the figure below.
I have 4 VPCs, each VPC has 3 subnets (1 for the VM instance and the other 2 for interfaces). Each VPC hosts a Cisco CSR 1000v in ...
0
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0answers
19 views
how to redistribute using EIGRP instead of my shortcut way [closed]
I used these commands to redistribute:
router ospf 1
redistribute rip metric 500000 subnets
exit
redistribute ospf 1 metric 0
end
I want to the redistribute using the eigrp?
0
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0answers
34 views
OSPF using a new MAN network [closed]
I am working on a MAN network setup. It is not live currently, we are using IPSEC VPN tunnels back to the main office for the remote offices of ours.
I am wondering how to setup from scratch OSPF to ...
2
votes
1answer
36 views
My OSPF Multi Area Topology is not reliable
I made an ospf multi area topology, but it's inconsistent. At times, host from the A area could ping to hosts in other areas however, sometimes otherwise (failed to arrive). Whenever I tried to do a ...
1
vote
1answer
37 views
OSPF inter-area traffic - not so direct after all
a) Can I confirm inter-area traffic will be routed towards Area 0 / Area 0 will be the transit network for all inter-area traffic?
b) Consider the diagram below
q1) Does R1 receive Type 3 LSA for ...
2
votes
1answer
30 views
%OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link
I have a topology like this:
this Router0-1's Gig0/0/0 ip: 10.0.12.1/24,
the Router0-2's Gig0/0/0 ip: 10.0.12.2/24, Gig0/0/1 ip: 10.0.23.2/24,
this Router0-3's Gig0/0/0 ip: 10.0.23.3/24,
at ...
1
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0answers
24 views
Whether the OSPF ABR Router's loopback network should announce to Backbone Area? [on hold]
The OSPF ABR Router whether its loopback network should announce to Backbone Area?
the upper snapshot shows the C,D,E are ABR Routers, if everyone has its own loopback networks, I want to know ...
0
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0answers
15 views
Is there any rule for select the Net Link's ADV Router? [duplicate]
I have a topology like this:
show ip ospf database
OSPF Router with ID (2.2.2.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age ...
1
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1answer
42 views
What's the definition of Router Link and Net Link?
When I show the ospf database:
Router2#show ip ospf database
OSPF Router with ID (2.2.2.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router ...
1
vote
3answers
75 views
Why the OSPF router do not have neighbor?
I have two Routers in the Cisco Packet Tracer:
Router2-1, Router2-2, Router2-3 all have their own loopback 0 with IP address 1.1.1.1, 2.2.2.2, 3.3.3.3.
I only launched the OSPF progress in the ...
2
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0answers
53 views
OSPF behavior for redistribute routes
I have 2 equal cost path links between PeerA and PeerB and all its interfaces are participating in the same OSPF area.
When i redistribute a static route (172.16.2.0/24) from PeerB to A, does the ...
0
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0answers
23 views
Zebra: Redistribute BGP over OSPF [on hold]
I am using netkit to simulate 2 AS:
One with 3 nodes interconnected using OSPF.
Other with 1 node using static routing.
I interconnect the AS using BGP.
Connection intra-AS is OK, but I am failing ...
1
vote
2answers
67 views
How to assign all interfaces in one router to OSPF backbone area?
Is there any command to assign all interfaces in router (CISCO 2691) to OSPF backbone area? I was using this command for each interface.
network address wildcard-mask area area-id
Where wildcard ...
1
vote
1answer
49 views
Quagga - Configure 3 routers using OSPF
Hi I'm trying to use quagga to connect 3 routers but the middle one doen't complete the path that a trace route command would do even though it knows where the target address is. It seems that ...
6
votes
1answer
212 views
OSPF and its use of Multicast
When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment?
My understanding would be without this, ...
3
votes
1answer
53 views
When do multiple routers connect to the same switch (ie for DR election process)
When studying for the CCNA we are presented with the 3 tier Cisco model below.
Then when we discuss routing protocols there are many images where these routers are connected in a switch and thus need ...
1
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0answers
49 views
OSPF peering not forming when authentication is enabled
OSPF peering between two of my routers went down 2 days before. After troubleshooting, I removed the authentication commands from both devices GRE tunnel interfaces
ip ospf authentication message-...
0
votes
1answer
35 views
OSPF DR and ABR relationship
I know the DR/BDR and ABR are of course separate concepts and serve different functions, but in many cases is the ABR router for a given area also made to be the DR? Or would the DR be more often an ...
3
votes
2answers
67 views
Routing Table Eligibility
I have an architecture which is that each remote site has 2 Dialer interfaces dialling into a virtual-template core which authenticates the sessions and applies attributes from a RADIUS server. OSPF ...
1
vote
1answer
64 views
MultiLayer Switch to Ping different Switches and routers under different VLANs [closed]
Hey Guys,
So this is basically a small design of a made up university which has 3 campuses( the 3 routers).Each connected to 1 College(Switch) and each college connected to 3 other Schools(switches) ...
1
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2answers
166 views
Prevent OSPF routes advertised by other routers from entering the routing table?
I have a fairly complicated scenario that I've managed to duplicate with GNS3. Please see the attached image. In this scenario I have four "Branch Offices" each with their own router connected to ...
0
votes
1answer
53 views
Prevent OSPF routes from one network from being redistributed to the rest of the network?
Synopsis: Network A needs to be able to use a static default route to Network B via a local connection (G0/0/3). Network A does NOT want to route ANY Network B addresses through the rest of its ...
1
vote
1answer
156 views
Cisco ASA context OSPF configuration issue
I've two cisco ASA configured in active/active HA. ASA is connected to switch with port-channel.
Switch configuration:
interface Port-channel47
description ASA2
switchport mode trunk
switchport ...
-1
votes
2answers
135 views
the difference between RIP and OSPF [closed]
I was working with CISCO and to create a path between switches my teachers told me that I can use 2 types of protocols,
but they did not explain to me what differences there are between the two:
...
3
votes
1answer
1k views
How to flush route cache in fortigate
Is there something like route cache on fortigate like in linux?
How can i clear this cache?
I have some problems with OSPF, after adding or changing redistributed network. Foritgate show routes ...
4
votes
1answer
71 views
Question about OSPF and Database Descriptions
After the adjacency as been formed between two routers, a master-slave-relationship between two routers is formed too, where the master begins to send Database Description (DBDs).
My question is: ...
1
vote
1answer
57 views
Why does OSPF function on Network Layer whereas RIP functions on Transport Layer?
As far as I know, OSPF creates its messages directly at the network layer, whereas RIP function on UDP. Their function is pretty similar, so why is there such a difference in their messaging practice?
1
vote
1answer
319 views
Broadcast,multicast and unicast in OSPF
In OSPF, routers from down to full state,what's kind of networks(broadcast multicast unicast) used per state to exchange information? I always heard 224.0.0.5 and 224.0.0.6 these two address, and was ...
3
votes
1answer
138 views
OSPF Area Design
Have a hub and spoke design where each Branch has a single router with a WAN connection to DataCenter1 Hub and another WAN connection to DataCenter2 Hub. There is no OSPF running elsewhere in the ...
4
votes
3answers
902 views
Configuring OSPF on two directly connected routers which are in different areas
I want to configure OSPF on the topology below. The problem is when I connect two routers to each other and when I config one router to area 0 and another one to area 1, they don't see each other as ...
3
votes
1answer
277 views
Why OSPF E1 and E2 exist?
I know the difference between E1 and E2 metric-types.
I know the preference level given to those routes.
I know difference between Metric and Forwarding Metric and how it works.
What I don't ...
3
votes
2answers
325 views
OSPF on tunnel interfaces
Can I keep different tunnel interfaces in different OSPF areas. Keep in mind that the physical interface is going to be the same
4
votes
2answers
154 views
How does a route-map applied as outbound on a neighbor sees the redistributed ospf routes into bgp? Local or external?
Here's my scenario:
Redistribute ospf routes into bgp
Create a route-map that matches on route-type=local and modifies the nexthop (to 4.4.4.4 for example)
Assign this route-map as outbound routemap (...
2
votes
3answers
169 views
Cisco Vlan block access
So I have 2 core switches and 1 access switch, I have the vlans 1, 10, 20, 30 and 100. Vlan 10 is voip and what I would like to do is stop anyone on the other vlans from being able to see that subnet, ...
4
votes
1answer
480 views
Why does EIGRP have lower Administrative distance than OSPF?
I have given the following network diagram and been told that,
Since EIGRP has a better (lower) administrative distance than OSPF, the router on the far left will use the EIGRP path and publish ...
2
votes
1answer
207 views
BGP with OSPF configuration question
ISP - Sending default route to sw1/2 via eBGP
sw1 - config
router ospf 100
network 0.0.0.0 255.255.255.255 area 0
default-information originate always
!
router bgp 100
bgp log-neighbor-...
1
vote
1answer
695 views
nexus ospf network statement missing
In old school IOS we used to do
router ospf 1
network 0.0.0.0 255.255.255.255 area 0
But in Nexus switch i am not seeing any command or related doc, how do i announce my subnet in ospf in nx-os
My ...
3
votes
2answers
241 views
OSPF - Default route doesn't get advertised to all areas
I am trying to find the reason why R1 doesn't have the default-route, propagated and generated by my Internet-PAT-Router, in his routing-table. The weird thing is, that R2 actually has an entry for ...
-1
votes
1answer
273 views
How to implement Layer 3 (OSPF, IS-IS) link redundancy?
I think this kind of topic may be a course basic, but I'm still have a lot of technical doubts on how to implement redundant links on Layer 3, for example:
-In order to use dual homing for a remote ...
3
votes
2answers
350 views
vPC traffic flow question
This is going to be new network in my datacenter and i have question related vPC, as you can see i have A1/A2 switch (L3/L2 routing) in aggregation layer and C1/C2 switches for Core (L3 routing). I am ...
1
vote
1answer
145 views
Is it required for an ABR to be connected to area 0?
The question "why is it required for all the areas to be connected to area 0?" is answered many times on the internet. However, I could not find an answer to the above question.
Please refer to the ...
1
vote
1answer
236 views
OSPF Area Multiple Subnets
Is it possible to have multiple subnets in one OSPF area? Everything I can find so far points to the answer being 'No', however I need to know for sure if it's possible or not. Our current setup is a ...
4
votes
1answer
84 views
OSPF - networks/links don't get advertised
In my Multiarea-OSPF configuration I can ping my neighbor, but nobody which is more than one hop away (for instance ABR2).
Also traceroute just shows "1 * * * - 2 * * * - 3 * * *"
Can ...
3
votes
2answers
499 views
OSPFv3 (newer commands) not working in Cisco Packet Tracer
The command
router ospfv3 1
is not working in the Cisco Packet Tracer (Router: 2811).
Does it work somehow or are the IOS version just not up-to-date?
1
vote
2answers
382 views
OSPFv3 - Sample configuration (Dual Stack IPv4 and IPv6) - Cheat Sheet
When configuring OSPFv2 on a router, you type in
router ospf 10
router-id 1.1.1.1
network 10.0.0.0 0.0.0.3 area 0
for example. That way the network can be advertised per LSAs.
But in OSPFv3 it ...
4
votes
2answers
203 views
Cannot see the differende between distance-vector and link-state
At link-state routing protocols each router advertises every link he knows about to the next router, which again advertises his links and so on until every router knows all links in his area. So every ...
2
votes
1answer
71 views
Clarifications about RIP and OSPF
What (I think) I know:
RIP uses a distance vector routing approach, where each node sends to its neighbors the number of hops one should take to get to other routes if one "started" from that ...
1
vote
2answers
320 views
Will an EIGRP route be chosen over an OSPF route regardless of metrics?
I am sure this has been asked SOMEWHERE but I can't find it anywhere.
Question is simple: Will R1 chose the EIGRP route to R4 over the OSPF route, even though the OSPF route is clearly the better ...
5
votes
1answer
244 views
Struggling inbound and outbound traffic engineering to/from iBGP peers at different POPs
We are a managed service provider running a small sized network in a single datacentre in Sydney. We've recently deployed a new POP inter-state in Melbourne (both are on the east coast of Australia), ...
3
votes
3answers
2k views
Why does MPLS need an IGP (like OSPF) in order to work?
I saw a network using MPLS, BGP and OSPF as main network protocols. I understand that BGP was used to exchange traffic with another AS, and OSPF was used as Internal Gateway Protocol. So, why to use ...
