OSPF design

Hi Guys,
I'm currently researching the possibility of the implementation of OSPF in our core network. First, let me share a topology. 
It basically concerns traffic from the subnets connected to firewall cluster 1 that is going to firewall cluster 2. That traffic passes through the core router. Currently, the core router is configured using static routes. Although that's working fine, we don't want to have this administrative overhead anymore and are therefore considering the implementation of OSPF.
Since OSPF uses the concept of areas, the information and discussion I haven't been able to find, is, what would be a good approach to the network design of this OSPF implementation.
For example:
-> Should we go with one "big" area 0 or should we put the router in area 0, the firewall cluster 1 in area 1 and the firewall cluster 2 in area 2? This part of the network (basically our core) can be considered stable, we will expect low convergence there.  The main advantage of multiple areas is that convergence is limited to a single area.
-> Since the firewalls have the default gateway pointed at the edge cluster, a stub area cannot be used. 
I'd love to hear your takes on this.

You can think of multiple areas if you do not require to send all routes from cluster 1 to cluster2 .. or you need to send summary addresses from cluster1 to cluster2 or you need some sort of filtering.. Else, everythng can be in one area 0  to keep configuration simple...

Similar Messages

  • Routed access OSPF design

    Hi All,
    I need some advise on the following design.
    I am designing a campus network using routed access with OSPF. I will have 3 tiers - core, distribution and access. I am looking to configure the core/distribution links in OSPF area 0 and then the distribution/access links in a non-backbone area such as 1. I will then be able to filter/summarize etc as the ABR boundary.
    I only have 2 links from my core to distribution layer and I'm planning to terminate them on separate distribution switches (dist1 and dist2), see attached diagram.
    The links facing the DC will be in area0 and the links facing the access will be area1 but what area should the distribution to distribution link be in? I understand that if it is in the non-backbone area1 then I will loose the ability to use the link to the second core as intra area routes will be preferred by dist1. Are there any other considerations here? Should I connect two links between the the 4500s and configure 1 link in area 0 and 1 link in area1?
    Thanks,

    Disclaimer
    The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.
    Liability Disclaimer
    In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.
    Posting
    About how many L3 routing devices, and how many subnets, do you anticipate?  Depending on that, you might one to consider a single area design.

  • OSPF design for branch offices across MPLS

    Hello fellow networking engineers,
    I want to implement OSPF in our network. We have multiple branch offices, all linked to an MPLS backbone.
    I know that in order to get linked areas, I would need to setup GRE tunnels between them, but I want to avoid static/manual configurations as much as possible. With multiple sites, it would become cumbersome to create a mesh real fast.
    Is running OSPF independent areas at each site, and simply redistributing over eBGP a valid solution? This will host voice and data, and will failover to VPN connection (Cisco ASAs) if the MPLS goes down.
    For the VPN backup links, I thought of two options. Either simply using the default route to send everything to the ASA in case of MPLS "death", or inject routes using IP SLA...
    Any input would be appreciated.

    Marc
    You don't GRE tunnels to link your areas if that is what you want to do.
    If the SP supports it then you can exchange your OSPF routes between areas and they will still be seen as inter area routes rather than OSPF externals which they would if you simply treated each area as isolated from each other.
    In effect the MPLS network becomes an OSPF super backbone area and your main site would also be part of the backbone area with all your other sites having an area each.
    You still redistribute your OSPF routes into BGP but with some extra configuration on both your CEs and the SP PE devices.
    Like I say you would need to check with your SP but it is possible.
    Whether or not you need or want it I don't know.
    Your other option is as you have proposed to treat each OSPF area as an isolated one and simply redistribute into OSPF at each CE. Then within each site all non local routes would be seen as OSPF external routes.
    Either way in terms of backup I would keep it simple and use a default route at each site pointing to the ASA device. I can't see what you gain from IP SLA because if the main MPLS link goes down at any site the only other path they have out is via the ASA so there is nothing really worth tracking.
    The only other thing I would mention is remote site to remote site traffic. If there is any then presumably with your VPN tunnels you would be doing a sort of hub and spoke where the hub is the main site so you may need to think about traffic coming in from one VPN tunnel and going out to another VPN tunnel on the main site ASA.
    This would only really be needed if two or more sites had to use their backup links at the same time.
    In terms of which is better ie. OSPF inter area across the MPLS cloud or OSPF externals I can't really say to be honest. With the MPLS networks i have worked on we ran EIGRP and simply treated each remote site as an isolated AS.
    If you are already running OSPF then you may want to preserve your existing areas so it would make sense to go with the inter area option.
    If it is a new setup then I don't really know the pros and cons of either so can't really comment.
    Perhaps others may add to the thread with their thoughts.
    Jon

  • OSPF link update-Basic Query

    I am new to OSPF. I have 2 basic querys on OSPF link update.
    1. How does one router communicates with every router in the OSPF area. Is it that each router communicates only with its directly connected neighbours? example.
    ROUTERA-------ROUTERB-----ROUTERC-----ROUTERD----ROUTERE
    Lets say link on RouterB connected to ROUTERA goes down. How does "ROUTERE" get to know about this? Is the communication is from RouterB to ROUTERC then to ROUTERD and then to ROUTERE?
    2. How does router handle(forward) multicast packets?
    Thanks

    Hello Avil,
    the way OSPF communicates depends on how your network is set up. In your case, it looks like all routers are connected back-to-back with point-to-point links. OSPF uses the concept of adjacencies: an OSPF router has an adjacency with a connected router, which means that they have the exact same view of the entire network. If you do a 'show ip ospf neighbor' on your RouterA and your RouterE, it tells you the adjacencies these routers have with other connected routers. Now let's say the link between RouterA and RouterB goes down. RouterC notifies RouterD, and RouterD notifies RouterE immediately by exchanging link-state packets.
    Keep in mind that on a multiaccess segment (where multiple OSPF routers are directly connected on the same segment), the concept of DR (Designated Router) and BDR (Backup Designated Router) comes into play: on a multiaccess segment, a DR and a BDR are elected, and all other routers have full adjacencies only with the DR and the BDR.
    Regarding the multicast traffic: it is handled just as unicast traffic (unless you specifically block it).
    Does that make sense ? If you are just starting with OSPF, have a look at the link below, which contains a pretty good introduction of the basic concepts.
    OSPF Design Guide
    http://www.cisco.com/warp/public/104/2.html#4.0
    HTH,
    GNT

  • OSPF IP addressing

    I have been reading a lot about OSPF design and tuning and I have been unable to find anything about IP addressing between routers in an area. OSPF elects a DR and a BDR for every broadcast domain so you can end up having multiple DR/BDR's in the same area. If you have all links between routers in the same broadcast domain, then there will only be one DR and BDR for that particular area; is that prefered? All routers still have to perform the SPF algorithm but the DR/BDR send out the LSA's to intra-area routers. Would all the routers being in the one broadcast domain save a little bit of bandwidth or processing power?

    It is a common misunderstanding to believe that an area should have a single DR and a single BDR. But that is not the case. In fact DR and BDR have nothing to do with areas.
    I think the situation that you describe might be like this
    RouterA has an Ethernet connection to RouterB
    RouterA has a separate Ethernet connection to RouterC
    RouterA has a separate Ethernet connection to RouterD
    RouterA has a separate Ethernet connection to RouterE
    So RouterA is a member of 4 separate broadcast domains. And yes RouterA would be DR or BDR in each of the 4 broadcast domains (assuming that there are not other routers connected to any of these broadcast domains). It is not necessarily an issue for RouterA to be DR or BDR in multiple networks).
    HTH
    Rick

  • OSPF area plan

    Dear All,
    I have an existing network setup, ISP1 connecting to the MPLS cloud that connects to other branch offices. ISP2 to connect to the outside world. I only have area 50 in my network and area 0 is at ISP1 end that is the MPLS cloud.I do not have info about ISP 2 's area 0.
    I would like to upgrade my network by using Nexus 5k's to connect to my servers . Also would like to run L3 between VSS Core and the N5k's.
    My question is how do i plan my OSPF design and to which area do i assign the new server farm to?(N5k's to the core VSS)
    Do i create a new area or use existing area 50?
    Do i create a totally stub as i am trying to minimize the LSA updates.
    Do i create new area 0 in my LAN network as it does not have Area 0 , but has got it only on ISP1's MPLS cloud.
    Or else is there a new plan?
    Please note that all my static routes from other branches in the MPLS cloud are redistributed into OSPF as this is the hub site and all the spokes will have to go through this Core VSS to reach outside.
    I am attaching the topology for reference.
    B1,B2,B3 are the branches where the MPLS clouds connect to.
    Thanks in advance

    If you are peering with ISP1 using OSPF which it sounds like you are then you definitely don't want to create another area 0 in your LAN.
    And if you created a new area that area also would need connectivity to area 0 and not via area 50 unless you configured a virtual link between area 50 and your ISP router
    However in general you should only use virtual links when you have to and the ISP would have to get involved if you wanted to configure it. So I would recommend against that as it complicates things significantly with very little gain.
    All you are really doing is connecting a pair of switches to your existing infrastructure and i can't really see the need to do anything other than add them to your existing area.
    I understand what you mean about the switches receiving all the LSAs for remote sites but i wouldn't have thought that would be a problem for Nexus switches.
    If it really was a concern then you say you are proposing to connect the switches with L3 to the VSS switches. If that was the case you could always configure routed ports with IPs and if needed configure default routes on the Nexus switches pointing to the VSS switches and configure static routes for the server subnets on the VSS switches pointing to the Nexus switches.
    Whichever you use i would make it as simple as possible so definitely no need for another area as far as i can see.
    Jon

  • OSPF AREA 0

    Hi,
    I work for a company and noticed they having everything in area 0. They must have well over 350 routers in the core. As I was studying my CCNP I new there was a limitation to having some many routers in area 0. I have been told that they way this is designed is with loads of point to point interfaces so /30 so at max there is only 2 interface performing in area 0 at each time. Is this correct? is this a good OSPF design?

    Disclaimer
    The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
    Liability Disclaimer
    In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
    Posting
    As both Paul and Rick have already noted, the real advantage of OSPF areas is containing how much information a router must (internally) manage for the OSPF topology.
    An old rule-of-thumb, was no more than 50 routers per OSPF area, but many variables are involved beyond just the number of routers.
    Newer "routers" are often much "faster", and on Cisco devices, there's an optional incremental SPF feature which might reduce some of the CPU cycles needed to (internally) manage the topology.  (NB: Cisco OSPF later OSPF implementations have other subtle ways of supporting OSPF that assist in supporting larger topologies.)
    So, as Rick also noted, just knowing there's 350 routers doesn't mean it's actually a bad design.
    PS:
    BTW, for your /30 Ethernet links, is OSPF p2p defined on the interfaces?

  • Border Routers

    With all the improvements being made, has there been any solution to monitoring a border router located on the other side of a firewall, other than manually adding it and setting up ICMP?

    Hi,
    Yes. Nerwork/routers in different areas can talktogether and it will be via Area 0.
    Have a look at the OSPF design guide for an idea on Areas of type of Routers.
    http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094e9e.shtml#t8
    A router that has all of its interfaces within the same area is called an internal router (IR). A router that has interfaces in multiple areas is called an area border router (ABR). Routers that act as gateways (redistribution)between OSPF and other routing protocols (IGRP, EIGRP, IS-IS, RIP, BGP, Static) or other instances of the OSPF routing process are called autonomous system boundary router (ASBR). Any router can be an ABR or an ASBR.
    Hope this helps.
    -VJ

  • OSPF Area Addition - Design Question

    Hello,
    I have a design question regarding OSPF. I am looking to add a new ospf area (1). The area will live on two Core routers and two Distribution routers. Can you please look at the attached Pics and tell me which design is better.
    I would like to be able to connect Core-01 to Dist-01 and Core-02 to Dist-02 with a connection between Dist-01 and Dist-02, but this will result in a discontiguous area, correct?
    Thanks,
    Lee

    I would say that the more common design is to have just backbone area links between the core routers. But there is no real issue with having an area 1 link between them...
    If I were you, I would not make the area a totally NSSA. Here are my reasons for that:
    - you will get sub-optimal routing out of the area since you have two ABRs and each distribution router will pick the closest one of them to get out to the backbone even though it may be more optimal to use the other one
    - in an NSSA case, one of the two ABRs will be designated as the NSSA translator, which means that if you are doing summarisation on the ABRs, all traffic destined for these summarised routes will be drawn to the area through that one ABR.
    Paresh

  • DMVPN Design Question - EIGRP or OSPF

    Hi,
    We are in the process of designing a DMVPN network, which will be used as a backup (over the Internet) to our MPLS WAN Network. Currently we are using EIGRP at central and remote site.
    If I select EIGRP as also the routing protocol for the DMVPN, then EIGRP will consider the MPLS WAN Routes as External (Since they are being redistributed through BGP from MPLS Core into our internal Core) and then DMVPN Routes will be preferred over MPLS WAN Routes. Is this understanding correct ?
    How can i correct this problem ? Using the 'distance eigrp ...' command ?
    Is there any advantage using OSPF as the routing protocol in DMVPN ? This won't solve the above problem but are there any inherent advantages of OSPF over EIGRP in DMVPN Design ?
    We have around 18 Sites that will be connected with no Spoke-Spoke functionality required.
    Thanks,
    Naman

    You really cannot use EIGRP effectively over the WAN. I was managing a 500 node DMVPN with a a redundant 6509 core. The results were unbelievable. The 1811's hanging off of the cores through the DMVPN's were crazy. Every time a change occurred, if one router lost its VPN connection, the EIGRP protocol would broadcast the changes to all of the cloud, meaning to all 499 EIGRP participants would have to be notified of the change. This was HUGE. OSPF has better NBMBA environments that you would use. Personally, you wouldn't have a choice. Using EIGRP with DMVPN's that are over 50 nodes are practically impossible. I did work around the issue and stabilized the network but knowing what I know now, definately OSPF.

  • Out-Of-Band Management over IPSec and OSPF Area Design

    Hello,
    i'm planning to implement Out of band management over OSPF over IPSec Tunnel and i have a question about the OSPF area design (please see attached figure).
    As network administrator our NOC is sitting in OFFICE (OSPF Area 1). Internet access is guarenteed over our DCs (Multihomed BGP peering).
    Additionally we have a second internet access at OFFICE where i want to use for IPSec Tunnel and building a OSPF neighboring to our Out-of-Band Firewall, which they too have theire own internet access.
    I'm planning to declare this IPSec Tunnel as OSPF AREA 3 and AREA 4 respectively for DC1 and DC2. There are no subnet overlapping.
    My Question is if I should connect both areas 3 and 4 at OFFICE to the backbone area over a virtual-link or not? Would be an disadvantage if i wont use the virtual-link?
    Thx for any reply

    1.The AUX port on Cisco routers is either RJ-45 or DB-25. If the AUX port is RJ-45, use a flat-satin rolled RJ-45--RJ-45 cable (part number CAB-500RJ= ), which is usually provided with every Cisco router for console connections. You also need an RJ-45 to DB-25 adapter marked "MODEM" (part number CAB-25AS-MMOD) to connect the rolled cable to the DB-25 port on the modem.
    2. if your router has a DB-25 AUX port, use a straight-through DB-25Female - DB25Male RS-232 cable to connect the modem to the router.
    Use this document.
    http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a0080094bbc.shtml

  • Design Help with MPLS/BGP and Point to Point VPNs using OSPF as backup

    I need some advice on the configuration I want to implement. Basically we have a MPLS cloud using BGP. We are using OSPF for internal routing. Everything is working fine. Now we want to add a Point to Point VPN using new Cisco ASA's for a backup path at all of our remote locations. We want it to be on standby. I want to use OSPF for this. Miami and LA are datacenters. I want the VPN's to go into both datacenters if possible running OSPF for backups. I have a feeling this will be very tricky. I also wanted to use floating routes. Now I know I get the VPN's up and running using OSPF with no problem. Here are my questions:
    But being that I am using different areas, will OSPF through the VPN work correctly? I have the Cisco PDF on setting this up but it looks like they are using the same, AREA0, in the example.
    Can I get both VPN's to work with no problems? Or will it be too much of a pain?
    What would you guys suggest?
    Thanks.

    We are implementing the same solution, and was only able to make this work using HSRP one router for the MPLS connection and one for the VPN tunnel. I opened a TAC case and the tech couldn't get it to work either. I was able to establish the Lan-2-lan tunnel but triggering the route update was the problem. We ended up pulling our ASA5505's out and putting in 1841 routers.

  • Please shed some light on Data Center design

    Hi,
        I want you guys to recommend what the design should be. I'm familiar with HP blade system. Let me clarify the existing device.
    1. HP Blade with Flex Fabric. It supports FCOE.
    2. MDS SAN switch for the storage
    3. Network Switch for IP network.
    4. HP Storage.
        HP Blade has 2 interface types for IP Network(Network Switch) and Fiberchannel(SAN).
       What is the benifit for using Nexus switch and FCOE for my exising devices. What should be a new design with Nexus switch? Please guide me ideas.
    THX
    Toshi 

    Hi, Toshi:
    Most of these chat boards have become quite boring. Troubleshooting OSPF LSA problems is old news. But I do pop my head in every now and then. Also, there are so many other companies out there doing exciting things in the data center. You have Dell, Brocade, Arista, Juniper, etc. So one runs the risk of developing a myopic view of the world of IT by lingering around this board for too long.
    If you want to use the new B22 FEX for the HP c7000 blade chassis, you certainly can. That means the Nexus will receive the FCoE traffic and leverage its FCF functionality; either separate the Ethernet and FC traffic there, or create a VE-port instantiation with another FCF for multihop deployments. Good luck fighting the SAN team with that one! Another aspect of using the HP B22 is the fact that the FEX is largely plug and play, so you dont have to manage the Flex Fabric switches.
    HTH

  • Layer 3 to the Access Layer and MPLS Design Considerations

    Hi,
    We are about to install a new network consisting of Cat 4500s with Sup7E at the Access Layer, with Nexus 7000 at the Distribution and Core layers.
    We have 14 floors with at least three 4500s on each floor. Within the office block where the Access Layer and Distribution Layer reside we need to support secure borderless networking using 802.1x to place users from different parts of the business into segregated networks at layer 3.
    All switches will have the feature sets to support MPLS/ VRF / OSPF / EIGRP / BGP etc.
    We quickly dismissed the idea of using VRF-Lite due to the sheer number of Vlans we would need to managage and maintain,  the point to point links alone just to get one additional VRF on each floor required far too many Vlans.
    As a result we are now considering deploying MPLS. The obvious benefits include scalability and manageability, the fact that all switch to switch links can now be routed, instead of having to using SVIs.
    My query is one of design surrounding MPLS and how this maps to an enterprise network with a routed access layer. Do Cat 4500s become the CEs and take part in MPLS / BGP and Label Distribution, or does the BGP peering and Label Distribution only occur between the Distrubtion - Core - Distrubtion layers, mapping to the PE - P - PE topology in an ISP environment, the access layer simply uses the IGP (OSPF in this case) to learn routes ?
    Any help would be greatly appreciated.
    Chris.

    Hi Andy,
    Thanks for your response.
    I have been doing a little bit more research it seems the Cat 4500s do not support MPLS!! Nor do Cisco have any plans to support it on this platform. I find this a little rediculous considering the level that Cisco are pitching this platform. With the Sup 7E only VRF Lite is supported, with plans to support EVN (which still uses trunk links for logical separation).
    So it looks like we are going to have to go back to the drawing board.
    (perhaps we should have gone HP or Juniper!)
    Chris.

  • How do you Redistribution EIGRP into OSPF and maintain a distance of 250 for a static route?

    Ok, I have scoured the forums long enough and have to post. The design is below. I moved a firewall to our new data center, which required adding some static routes for VPN connections and broadband backups. To minimize the amount of static routes I redistribute static into EIGRP with a route-map and prefix-list.
    My problem is the next part of my network. When the data leaves my 56128's it hits an edge device connecting to our dark fiber. On this edge device I am running OSPF onto the dark fiber, then redistribute some EIGRP subnets into OSPF and again all is well.
    Everything works up until the point the redistributed routes hit my RIB at my main data center where I am running IBGP. IBPG is run between our MPLS router and core for all our remote sites. When my backup route from the 56128's hits the cores, it supersedes the BGP route because the AD route O E2 [110/20] is lower than the BGP AD B [200/0]. Given the configuration below what can be done to remedy this? Oh when I redistribute I can only change the AD for the backup routes, all other routes should stay the same.
    56128's where my static routes are:
    ip route 192.168.101.0/24 192.168.30.77 name firewall 250
    router eigrp 65100
       redistribute static route-map Static-To-Eigrp
    route-map Static-To-Eigrp permit 10
       match ip address prefix-list Static2Eigrp
    ip prefix-list Static2Eigrp seq 2 permit 192.168.101.0/24
    Edge device:
    router eigrp 65100
     network 172.18.0.5 0.0.0.0
     network 172.18.0.32 0.0.0.3
     network 172.18.0.36 0.0.0.3
     redistribute ospf 65100 metric 2000000 0 255 1 1500
     redistribute static metric 200000 0 255 1 1500 route-map STATICS_INTO_EIGRP
     passive-interface default
     no passive-interface Port-channel11
     no passive-interface Port-channel12
     eigrp router-id 172.18.0.5
    router ospf 65100
     router-id 172.18.0.5
     log-adjacency-changes
     redistribute eigrp 65100 subnets route-map EIGRP_INTO_OSPF
     passive-interface default
     no passive-interface GigabitEthernet1/0/1
     no passive-interface GigabitEthernet1/0/2
     no passive-interface GigabitEthernet2/0/1
     no passive-interface GigabitEthernet2/0/2
     network 172.18.0.0 0.0.255.255 area 0
    ip prefix-list EIGRP_INTO_OSPF seq 5 permit 172.18.0.0/16 le 32
    ip prefix-list EIGRP_INTO_OSPF seq 10 permit 192.168.94.0/29 le 32
    ip prefix-list EIGRP_INTO_OSPF seq 15 permit 192.168.26.32/29 le 32
    ip prefix-list EIGRP_INTO_OSPF seq 20 permit 192.168.30.72/29 le 32
    ip prefix-list EIGRP_INTO_OSPF seq 25 permit 192.168.20.128/25 le 32
    ip prefix-list EIGRP_INTO_OSPF seq 26 permit 192.168.101.0/24 le 32 <- Backup Route for MPLS Remote Office
    route-map EIGRP_INTO_OSPF permit 10
     match ip address prefix-list EIGRP_INTO_OSPF

    So in the case of a /24. If it were say broken up into /25's? From our remote sites we are using aggregate-address summary-only. Not sure how I would advertise a more specific route via BGP, sorry.
    I didnt have this problem until I moved my firewalls. They plugged into the cores where IBGP was running and the static never kicked in unless the bgp route disappeared. I guess I could use my static redistribution for my VPN sites and use statics across the cores for the handful of backup links I have.

Maybe you are looking for

  • How do I stop iPhoto from auto-launching?

    I'm running the latest version of OS X and iPhoto, this has been going on for 2 years or more and I still can't figure out a solution. So I figured maybe something new is out there where someone might have a clue why I'm experiencing this. I cannot k

  • Creating a fill-in calculating form

    I am trying to create a fill-in form that will calculate figures (addition, subtraction). It's a 3 column form, with the last column as a total column. I would like it to calculate automatically.  This is going to be a network form.  Is this possible

  • Currency format issue

    I have a currency column need to display the data 4000000.00 as $4,000,000.00 ie;basically need to have a comma in the format. is there a function which can do this instead of setting the format at the SQLplus prompt? Thanks

  • Photoshop Elements 9 Layer Mask Difficulties

    Hi, I am trying to use the Photoshop Elements 9 layer mask tool but every time I brush over my image to hide sections of it, the image merely becomes faded-out, as if I were using a brush with a low opacity. However, my brush opacity is at 100%, as i

  • Elements 3 windoww 7

    Photoshop elements 3 when installed onto Windows 7 does operate correctly. Mainly when duplicate layer is selected the new layer appears  with a grid if some other image superimposed. Are there any fixes available?