EoMPLS, EoSDH, E-VPn etc.

FrankGuthrie

Ok, so Ethernet is carried over MPLS and SDH, but this is kinda confusing me.


MPLS and SDH are not the hardware itself... so what are these called in the big picture. SDH and MPLS are running over a certain type of physical hardware, but Ethernet is on its turn running over MPLS and SDH


I know Ethernet is a protocol uses to communicate in a LAN environment. Nowadays Ethernet is also used over the WAN, bit this is confusing me as I'm used as seeing Ethernet running over UTP. Now the Internet does not exist of UTP, but consist Fiber and other types of cabling (I think), but I'm worrying I'm not seeing the picture some times..

For example we have a customer connecting to our network (provider) and according the drawing the connection is E-VPN. What difference is there with normal (!?) VPN??

- Now I'm wonder E-VPN is Ethernet VPN, but over what kind of hardware is running?
- According a colleague the E-VPN running over and MPLS cloud, this is confusing me more. What type of line is used to terminate at both end? When I look on our switch connecting to the customer, it look like it's just a nomal ethernet line configures as an access port...... I can't image there is an UTP line running to the customer seeing that UTP has limitations.
- Why isn't Ethernet not used everywhere. It seem them can run Ethernet over all types of hardware these days...Why do you have the need for other networking protocols. Having other protocols is confusing me.

Same goes for FCoE. Fiberchannel runningover Ethernet. This seems to be redundant. A protocol running over another protocol...

networker050184

Ethernet doesn't just run over UTP. You can also run Ethernet over fiber in your own LAN. In the WAN providers put Ethernet and MPLS frames into SONET/SDH frames for transport over long haul. Think of it kind of like a GRE tunnel. You put an IP packet inside of another IP packet for transport. When it gets to the other side the top level IP header is ripped off and you have the original IP packet. Same with SONET/SDH. It presents the original frame or packet to the router on the other side.

FrankGuthrie

But what is the advantage off running Ethernet over a Fiber network?

Why do you want to do this is you can run it over UTP which is much cheaper.

networker050184

What else would you run? You still need a L2 protocol. Ethernet is easy and well known.

UTP is cheaper sure, but it has distance limitations which are far exceeded via fiber.

FrankGuthrie

So If we talk about E-VPN it's probably running over fiber and the last part is Ethernet?



At work I saw a customer connecting to a 2960 (L2) switch of ours. This confused me because I'm used to think in terms of a Router being at the 'edge'. from there the traffic move to a L3 switch in the environment which is connected to the vlan where the customer has its servers running. I saw this E-VPN connected to an Ethernet interface with a access vlan configures on our switch (Provider). How does this work. Did not know this was done like this.

This loook like the customer is part of our network at Layer 2.

I'm wondering how this works. Where in the path does this switch over to Fiber?

networker050184

I think you are confusing the layers of the OSI model here. It doesn't matter if it is fiber or UPT at L1, Ethernet is a L2 protocol. You can have a single 2960 switch with UTP and fiber connections. It's still Ethernet regardless.

As far as how does it appear to be a single L2 environment over the WAN is MPLS. The Ethernet frames from one site are encapsulated into MPLS packets while they traverse the providers network. Once it makes it to the other side the MPLS is stripped and an Ethernet frame is handed off to the customer. Again, UTP or fiber makes no difference here.

FrankGuthrie

I think that I am indeed confusing the OSI layers at bit maybe because in my head it was engrained that Ethernet and UTP are one and the same.


It looks like Ethernet is the Layer 2 protocol to beat the coming years... Am I wrong? What is it keeping it from becoming dominant?

Am I also correct that when you run Ethernet over SDH (EoSDH) and Ethernet over MPLS (EoMPLS) it is being encapsaulated extra as SDH and MPLS are protocols and not defining Layer 1 hardware? Correct?

deth1k

Actually fiber is cheaper than copper now...

networker050184

Ethernet has become dominant. And yes, you are getting the gist of it.

FrankGuthrie

Then I have another question, why do we need the extra encapsulation layer


Why not send Ethernet directly over whatever layer 1 infrastructure SDH is using, so without the extra encapsulation/overhead?

I guess fiber is becoming cheaper because they can send everything over copper. I think Fiber was there for speeds, but they are reaching the same speed over copper, so Fiber might become obsolete.

shodown

Ethernet changes at each interfaces mac address as you move it around networks. Someone correct me if I'm wrong.

deth1k

Fiber will never become obsolete, don't fool yourself. Fiber is future proof, next time new standard comes out all you do is swap out a line card (example: TM-Series - Products - Transmode). Also don't forget about distance limitation of copper, transatlantic copper possibility? :P

networker050184

You need the MPLS encapsulation because you can't just switch a frame over a routed provider network. SDH is used to multiplex circuits over long haul with very low latency.

Copper won't replace fiber for long distances. It is much faster to shoot light over an optical cable than it is to send an electrical signal over copper.

FrankGuthrie

Hi Guys, thanks for the replies, I think i'm starting to get it

FrankGuthrie

networker050184 wrote: »

You need the MPLS encapsulation because you can't just switch a frame over a routed provider network. SDH is used to multiplex circuits over long haul with very low latency.

Copper won't replace fiber for long distances. It is much faster to shoot light over an optical cable than it is to send an electrical signal over copper.

Hi networker,


I just wanted to make sure I got your you explanation right.


So If i want to send Ethernet over long distances UTP obviously has it limitations (100 meter and the the signal needs to be boosted/replicated/repeated).


So for this I need to send Ethernet over Fiber. As there is no standard for Ethernet over Fiber, Ethernet is encapusaled in other standard which can run of Fiber, correct?

adajanie

fiber optical connection is better than others now.