Questions tagged [redundancy]
For questions about network redundancy. For instance: you need to design a new network with high redundancy or you are troubleshooting an issue where it doesn't work.
106
questions
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Cisco ASA site-to-site VPN failover
We recently replaced international MPLS with new ASA 5510s and site-to-site VPNs. However, when we deployed this we ran into a problem where each remote location has 2 ISPs for redundancy, but when ...
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Why are rings not a favorite option in IT networks?
I'm an engineer in the automation field. I've been switching slowly to networking. I've started in the automation world 12 years ago.
With an automation mindset, we use rings (like MRP rings) ...
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Redundancy between router and servers
In the past, I was using a NetGear GS724T between my router and my servers. Unfortunatly the switch suddenly died.
Now I've changed it for a GS748T and also bought one more and I am wondering how I ...
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3 subnets, 2 OSPF areas - Will This Work?
Will any issues occur if I have a topology involving 3 subnets and two OSPF areas where one subnet is in AREA 0 and the other two subnets are both in AREA 1?
For example:
[area 1, subnet 1]---[ABR #...
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Firewall Replication
If I have two datacenter sites that are considered redundant to each other. Is it possible to sync firewall configuration from the primary to the backup? What is the best way to keep both firewalls ...
- 223
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3
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I have a single ethernet switch. Should I use spanning tree?
I have a single ethernet switch. Should I use spanning tree?
If there is a redundant link, definitely need to enable STP.
In a single switch, how is it possible to have a redundant link?
Any other ...
- 155
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votes
1
answer
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Juniper SRX HA links passing through switch
it is necessary to join two srx650 in chassis cluster (Passive/Active) via two switches EX4200 . I need to choose one from three examples.
Please , help to define correct choice and describe what the ...
- 397
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3
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10Gig over single strand fiber
We have several BX SFPs in my network and I love them. We're limited on the amount of fiber we can get between buildings (each pair costs $250/month) so the mismatched laser solution gives us ...
- 1,793
8
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4
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Expanding an HP IRF topology
I'm examining options for a future expansion of our infrastructure. We rent space at a colo so we don't have a dedicated datacenter of our own. This means that our next major expansion will likely ...
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2
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Will STP lose data whilst switching from a failed link?
In a network with a dual-redundant link between two switches, will any data be lost during the switchover from an active link to the blocked link when the active link fails?
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5 nines, how is it built from 4 nines links
How is 5 nines calculated using lesser reliable links?
For example, we have 2 x 4 nines connections used in an active/active setup... which supposedly equates to 5 nines, but I don't buy it... how ...
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Redundant IP link aggregation for failover operation without route failure detection
I am looking for a technology to achieve TCP connection fault tolerance with the help of two links between hosts and without time delays for route failure detection. Something like this:
...
- 205
7
votes
2
answers
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Configuring redundancy using floating static
I wanted to post my network layout, but I dont have the required reputation. So I have made up a network diagram below:
ISP
/ \
/ \
/ \
HQ------Branch
| ...
- 71
7
votes
1
answer
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CISCO 4500R+E, Sup7L-E redundancy: RPR or SSO?
We are going to deploy 4500R+E chassis with two redundant supervisors Sup7L-E.
All ports in chassis - switchport with trunks. L3 interfaces - SVI. Chassis wll terminate L3 domain (route between zone),...
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3
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Two ISP bgp topology?
We use palo-alto firewall as an internet gateway. We have 16 static ip-addresses. One is used for outbound traffic (users browse internet) . The rest is used for inbound traffic (mail server, ...
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0
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HSRP IPv6 configuration
Looking at the Cisco documentation for HSRP IPv6 configuration I noticed the use of 'standby 1 ipv6 autoconfig'.
interface FastEthernet0/0
no ip address
duplex auto
speed auto
ipv6 address 2020:...
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In and Outbound Dual VRRP connections
I'm trying to setup a redundant route link for our internal network using brocade layer 3 switches. I have setup up VRRP on both the green/blue and red/black networks. The reason for doing this is to ...
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Network Ten LTE Hubs Into One Network
I'm working through a tricky situation getting a field office set up out in a very rural area. There are ten 12' x 60' trailers being set up (2-3 metres apart from one another), each with varying ...
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Dual ASA5510 with dual ISP failover
I am setting up a highly redundant network and want to run my two ASA's in failover mode - each with a link to a router connected to two different ISP's.
The topology:
My two 2911's are running BGP ...
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6
votes
1
answer
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WLC geographical redundancy
There are two "central" locations each one having one satellite or spoke site. Let's have:
- zone A and its spoke_zone A1
- zone E and its spoke_zone E1.
Both region A and region E have a similar ...
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6
votes
2
answers
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Connect one router to layer 3 3750-X stack for redundancy
I'm connecting a Cisco 2851 router to a Layer 3 3750-X stack (2 switches). The Gi0/0 interface connects to an access port on the stack master.
How can I achieve redundancy from the 2851 to the ...
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5
votes
2
answers
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HSRP + OSPF over tunnel interface
We have 3 sites over an MPLS. Each site has 2 x Cisco 2911's running HSRP. Each site has a tunnel interface from it's local site to the remote site over the MPLS. The tunnel interfaces are mirrored on ...
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5
votes
3
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How to design IXP with redundancy?
With two route servers, one of them for redundancy, making peering for ISP's Do I have to make peering between the route servers? Despite of each route server would have all the prefixes for each ISP'...
5
votes
2
answers
740
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Cisco 4510R+E: Can I safely use SFP interfaces on the dual sup's to interconnect switches?
I am deploying a new Cisco WS-C4510R+E unit in an IDF. We have an existing C4510R+E in our main data center room (core switch), and I need to connect the new 4510 to the core one. I'd like to use the ...
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3
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Dual Circuit Health
I would like to know best practices for failing over onto a secondary MPLS or Internet circuit. I understand the concepts behind BGP and influencing in and outbound routes, however what I am looking ...
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votes
1
answer
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How does STP convergence work?
Consider the IEEE 802.1D (first revision) Spanning Tree Protocol. I have read a lot of articles and forum entries about STP convergence. Often I do find contradictions about the convergence mechanics. ...
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5
votes
1
answer
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Is it bad practice to use a Virtual Router for NTP-Clustering?
I'm trying to find information on whether it is possible to enable an NTP cluster containing multiple routers, that are configured with VRRP to share the same address.
I am aware that with many ...
- 53
5
votes
2
answers
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Clustered ASA with Dual WAN Redundancy
Let's assume there are two firewalls (ASA) clustered together and two routers (1800 and 2900) each with it's own WAN link. The two routers are managed from the same ISP (it's just link redundancy).
...
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Can I use an unmanaged switch as a substitute for redundant, stacked switches when using a single network card?
I am building a network with stacked switches for redundancy. The problem I have is that some of the machines connected to the network will only have one available network card. This card is not a ...
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votes
2
answers
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Network Redundancy with LACP Trunking
I would like to set up a redundant link between two switches. I have four ports available to accomplish this.
Scenario A: Switch 1 has ports 1+2 trunked together via LACP. They are plugged into ...
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4
votes
3
answers
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Redundancy in Internet core and edge networks - redundant devices and redundant links
Since inception, the resilience of the Internet has been based upon multiple paths from source to destination. At the granularity of the AS, this is generally implemented by linking to more than one ...
4
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2
answers
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Master stack switch turn off
I have two switches in a stack. One is master and the other is a slave. If I turn off the slave, the master will work with no problem. My questions:
if I turn off the master, will the slave still ...
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votes
2
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SonicWALL HA w/ Dual WAN HSRP from two redundant switches
We're adding two SonicWALL NSA 2600 firewalls to our current setup. We currently get two WAN connections from two separate Cisco routers running on the same external subnet with what I believe is HSRP....
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votes
1
answer
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Is it possible to design an E1 redundancy with failover router and single E1 WAN link?
We have a single E1 line from ISP at one site, and a backup E1 line at other site. RAD DXC-10A have 4xE1 ports and used as E1 cross-connect. At each site we have single Cisco router with no backup. Is ...
4
votes
2
answers
427
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OSPF Issue, redundancy between P2P (MPLS) and Firewall
I drew a diagram for the network to make it easy to understand my network issue.
Site B,C and D communicate through MPLS and in case of failover they
communicate through VPN tunnels.
Site X ...
- 41
4
votes
1
answer
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link redundancy
In a scenario, there are three devices R_A, R_B, R_C and connected as shown in diagram,
How can implement that Link 1 and Link 2 work in active and standby mode i.e. Link 2 will be active if Link 1 ...
3
votes
2
answers
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Connect two routers to a single uplink for full redundancy
I have a single uplink with my ISP at a data center. I have 2 routers (CISCO 3850). How do I connect these routers to that uplink WITHOUT a network switch? That switch will be a single point of ...
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votes
1
answer
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Cisco - supervisor reset without disabling interfaces
After power loss we have an issue with supervisor on 4500~ cisco switch.
Peer (slot: 3) information is not available because it is in 'DISABLED' state
But interfaces that are in that card are ...
- 31
3
votes
1
answer
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Cisco HSRP with redundant links
I am not sure how to configure HSRP in my scenario:
I have 2 distribution 2950 switches, each connected to two core 3560 switches.
Distribution switches work in VTP transparent mode and (for now) ...
- 133
3
votes
1
answer
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High Availability for ISR 4431 IPSec VPNs
I have the following lab setup in GNS3. R1 & R2 are VPN endpoint at my datacenters and R3 is simulating a remote site. What i'm trying to accomplish is having one tunnel from R3 to the ...
- 208
3
votes
1
answer
934
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HPE IRF Stack why do I need two physical ports?
I'm building exactly the same topology, but there is no explanation why do I need two physical interfaces in IRF stack?
So, can someone please explain me, why do I need two physical members in IRF ...
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votes
2
answers
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How fast can STP, RSTP, and MSTP find a new route?
If I have two switches connected redundantly and both are capable of using STP, RSTP, or MSTP, how quickly can an alternate route be detected and normal communication resume if the main route is ...
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votes
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Can links be aggregated in a way that provides packet level redundacy?
For the sake of the argument, let's talk TCP/IP, but if other technologies are more suitable, by all means, please say so!
My understanding of classic link aggregation is a round-robin type send ...
- 155
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votes
1
answer
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Switch Redundancy with Dell N2000 series switches
I've just set up a rack with a SFP input into a Dell N2024, with a /28 routed to the switch which I can then use as required for devices within the rest of the rack.
This is working fine from a ...
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2
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How to achieve Redundancy/Failover for two WAN links (not ISPs) ?
We have two wan data links (with two different telecom providers) going from our central office to a remote location. Each data link currently transfers data from different equipment that are in two ...
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votes
2
answers
884
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Can LACP connect to 2 different firewalls?
I'm in the process of redesigning my network and have a few questions about LACP configuration:
Can LACP be set up to connect to two different firewalls?
In the diagram I provided, there are three ...
- 33
2
votes
2
answers
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SRX chassis cluster over layer 2 network
I need to setup a chassis cluster between two SRX650s over a layer 2 network. I have found an article which is applicable to my situation.
But I do not understand some portions:
Please explain the ...
- 397
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votes
3
answers
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Fault tolerance with 3 routers in Packet Tracer
Given the following diagram, I've modified the static routing tables with an entry for each router of the other two, through the serial interface, and everything works fine.
What should I change so ...
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votes
2
answers
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Adding a secondary route non-stackable switch group
I believe I am missing something obvious. I am using GNS3 to lab out having two paths to a CORE network. See picture. The configuration works as I imagined, I can ping from each Switch every other ...
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1
answer
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4507r Supervisor engines aren't operating redundantly
The tl;dr : I have two supervisor engines in a 4507r but the standby unit doesn't appear to be ready to perform when the active module dies.
On Sunday I had a network problem that appeared to be ISP ...
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