If an organization in a city (perhaps New York) has multiple offices within that city, how would they interconnect their LANs? I already understand that they will connect to an ISP, but my question is: Does a MAN travel across the internet to connect their networks where they have routers running eBGP?

3 Answers 3


There are quite a few possibilites.

  1. They can get a dark fiber from an ISP and interconnect their network equipment, in this case they "own" the whole network and they are fully responsible for routing between different offices.

  2. They also can get plain Internet access in each location and build a secure overlay network, like DMVPN. The branch offices of course can run BGP with ISPs.

  3. Another option is to get some sort of L2/L3 VPN from an ISP. In case of L2VPN the offices will be directly connected in L2. In case of L3 VPN, the company's equipment usually will have to run some sort of routing protocol with ISP, who will "own" company's core network.

  • 1
    Dark fiber is a possible solution, but a really expensive way to go unless you require access to the glass... Feb 14, 2014 at 10:44

Metropolitan Area Networks (MAN) connectivity is wide range of connectivity act between LAN and WAN networks

To connect multiple offices of same organization within city , there are possible options

  1. Can connect with point to point lease lines and Configure static routing among this site's between two offices

  2. Built IPsec Site to Site VPN tunnels between two offices and Configure routing on tunnel to pass interesting traffic among tunnel .


enter image description hereFrom techopedia - It does establish it connection through an ISP so it travels the internet

Metropolitan Area Network (MAN) Definition - What does Metropolitan Area Network (MAN) mean? A metropolitan area network (MAN) is similar to a local area network (LAN) but spans an entire city or campus. MANs are formed by connecting multiple LANs. Thus, MANs are larger than LANs but smaller than wide area networks (WAN).

MANs are extremely efficient and provide fast communication via high-speed carriers, such as fiber optic cables.

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    FYI, a MAN is never considered "the internet". Typically MAN services themselves are all layer1 or layer2, transported on Ethernet over SONET or some other SONET payload; although there is no one way to build metro access... this happens to be the one that I've seen the most. Sometimes you see a MAN circuit terminated to an ISP for access, but that's not the same as a MAN traveling through the internet. Feb 13, 2014 at 11:44
  • It is not the internet, but it goes through an ISP to interconnect LANs. And as far as I know the ISP is in the "internet" and it's a WAN. How would you then physically connect multiple LANs if it does not connect to the "internet" through an ISP.
    – chris
    Feb 13, 2014 at 13:32
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    There are packet-switched technologies that don't connect to the internet, which is what Mike is talking about with EoS and SONET. If you're using a SONET connection to provide a reliable OC connection to another site, it doesn't have the ability to talk to anything other than the intended, pre-provisioned destination. So no, it isn't on 'the internet', it just happens to be traversing an ISP that also provides internet access.
    – Ryan Foley
    Feb 13, 2014 at 14:10

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