I don't rally care about the uptime at the spokes. It's not my responsability to maintain the spokes sites, we'll just give communication to our network.
I know that I'll have single point of failure in my topology, like having just one HUB, but I just don't want a spoke interfering in the opeartion of my network. Ex.: I don't want a eletrical failure at one spoke interfering in the operation of other spokes... Thanks for your reply. :) 2011/3/21 Michael K. Smith - Adhost <mksm...@adhost.com> > > On 3/21/11 5:36 PM, "Livio Zanol Puppim" <livio.zanol.pup...@gmail.com> > wrote: > > >Hello, > > > >I don't know if this is the appropriate list for this kind of subject, so > >if > >anyone knows another specific list, please tell me... > > > >I'm analysing several DWDM designs to implement at my city, but I'm still > >a > >bit confusing about the Metro acess design. I'm supposed to build a > >physical > >ring topology with 6 pairs of fiber with an hub-and-spoke logical > >topology. > >The ring will have about 40Km. At the HUB we'll install our > >point-of-presence with a MPLS equipment, and at the spokes we'll use only > >IP > >routers. We need an flexible design where we can add or remove spokes as > >needed with the minimum effort possible. We are planning to have, at a > >initial deployment, about 200 hundred spokes, and all these spokes are > >talking only with the HUB site. Everything should work like in an FTTH or > >FTTB design, no other type of transportation is allowed (wireless and > >copper). > > > >We can't use SONET/SDH. The solution must be only IPoDWDM or complemented > >with TDMoIP at the access equipment. > > > >The problem, is that all documents that I'm reading specifies that we > >should > >be worried with faults scenarios at the spokes, so that the optical > >network > >does not stops. For example, if the OADM equipment at the spoke is down, > >the > >lambda dropped at that site will be down too... Or at least, if we use a > >lot > >of lambdas, we need to keep and eye at the points where we have > >regenerators. > > > >We need bandwidth from 10Mbps to 1000Mbps at these spokes. > > > >My question is: > >Is it possible to make such a network in a way that we don't need to worry > >about faults (electrical or others) at the spokes? If so, how can I do > >this? > > > >I don't want the spokes sites interfering directly at the operation for > >the > >whole network. > > > >Thanks for your help. > > > Hello Livio: > > At some point you will have a single point of failure, it's just a matter > of where. If you are running a single-threaded lambda or set of them into > a spoke site, that node will go down should your transport gear fail. If > you want your add-drop sites to be redundant through the network layer you > will have to feed each spoke site from the East and West side of your ring > on separate add-drop gear. > > That will be expensive. If price is no object, you can do that and then > use your upper layer protocols to determine path availability. Or, you > can build your add drop site with a single device and built-in redundancy > (controller cards, power supplies, etc.) to keep the cost down. > > Long story short, if you need those sites to stay up regardless of > anything else, you have to build two of everything at each site. It can > certainly be done and many a vendor would like to talk to you about > solutions I'm sure! :-) > > Mike > -- > Michael K. Smith - CISSP, GSEC, GISP > Chief Technical Officer - Adhost Internet LLC mksm...@adhost.com > w: +1 (206) 404-9500 f: +1 (206) 404-9050 > PGP: B49A DDF5 8611 27F3 08B9 84BB E61E 38C0 (Key ID: 0x9A96777D) > > > > > > > > -- []'s Lívio Zanol Puppim
