The single-port method is what Telrad recommends for centralized EPC deployments, and multi-port is (the way I read the docs) only recommended/intended for EPC-at-each-site deployments. (You can make it work with centralized EPC, but there are many indicators that this feature was never intended to work this way.)
But the single-port method will inevitably always have some traffic hairpinning occur, which is the main reason why I don't like it. It doesn't matter if you are routing or bridging between your Compacts and your BreezeWay: the user traffic comes in on the PDN VLAN to the EPC, then gets encapsulated in GTP by the EPC, and finally gets turned right back around on a different VLAN and sent back out the exact same port on its way to the ENB. So not only does the traffic cross that particular ethernet port twice on the EPC, but assuming that you have your EPC plugged directly into a router as we do, the same traffic from the internet to your users will traverse your PDN router on at least three ports: once coming from the internet, twice going-and-coming to/from the EPC, and then once more on its way out to an ENB. This traffic flow wouldn't look any different regardless of whether you are trying to route between EPC and ENBs or bridge/switch. In your (Tristan's) case, I am a little confused by your description. If I understand you correctly, you have a switch physically located close to the WIB that you have the EPC plugged into, then a Mimosa path to a site somewhere where you have another router and (presumably) one or more ENBs, and you have the gateway addresses for the management and bearer VLANs sitting not on your WIB but on the router that sits at the other end of the Mimosa path. Do I have that correct? If that's right, you presumably have the WIB and the close end of the Mimosa path plugged into the same switch with the EPC, and then have the VLANs trunked like this: WIB port on switch: PDN VLAN tagged EPC port on switch: PDN, Mgmt, and Bearer VLANs tagged Mimosa port on switch: Mgmt and Bearer VLANs tagged With that arrangement, presuming that at the remote site the ENB is also being trunked the management and bearer VLANs directly, it matters not one whit which router on your network you put the .1 (or whatever) addresses on for the management and bearer subnets. In fact, you could get away with not putting those addresses on any router, and not even bothering to set the next-ip-gateway for the 'bearer' and 'external-management' network configs on either the EPC or ENB. It would all still work since the EPC and ENBs are all talking to each other over the same ethernet broadcast domain. This isn't an entirely bad set-up, either, because the WIB never sees anything but the PDN traffic, and the only device that encounters the traffic hairpinning is the switch that the EPC is plugged into. But since it's a switch (and presumably a modern-enough one), it is non-blocking / has enough backplane capacity for all ports to be moving their rated speed in each direction simultaneously. So, who cares. Now, if I've misunderstood and you actually both want and are working to achieve a routed set-up, and the bearer interfaces of each ENB will be in their own subnet(s) apart from the bearer subnet on the EPC, then where the gateway address sits for the EPC's bearer subnet will of course matter and have an effect on the flow of traffic between it and the ENBs. -- Nathan From: [email protected] [mailto:[email protected]] On Behalf Of Jeremy Austin Sent: Tuesday, January 31, 2017 3:40 PM To: Tristan Johnson; [email protected] Subject: Re: [Telrad] Setting up EPC Tristan, this fits into the discussion Nathan and I were having -- I'm currently using the single port method, and he is not. From what I can tell, Bearer traffic will use the bearer gateway, and management traffic will use the management gateway. I do not believe that there is any doubling back, so to speak. There are some firewall rules that Nathan can describe in greater detail, much of which you can find in the list archives. I have been finding radically different iperf behavior when testing the EPC's management interface directly on L2 vs. L3. I do not yet know whether this dichotomy affects bearer traffic; if anyone can confirm that would be awesome, as Telrad design docs appear to support both setups. I am possibly leaning toward Nathan's topology of porting all ENB traffic back over VPLS, as I already have a full MPLS stack available. On Tue, Jan 31, 2017 at 11:59 AM Tristan Johnson <[email protected]<mailto:[email protected]>> wrote: Hey guys, Working on getting our Telrad test gear going after, um, a couple years now. (long waits and contract failures at some tower sites perfect for LTE). I've been working on getting the EPC working, and we do have our EPC and EnB set up and functional. But, I'm curious if I have this configured in the most effective and efficient way.. I'll be perfectly honest, I'm not a switch guru, or VLAN man. I've routed from day one, and never really used VLANs (strange as it may be). So we have an OSPF routed network, and I'm trying to put the EPC at our head end. It goes something like this. (AZOTEL WIB router w/PDN vlan and another subnet for BH traffic from the rest of our network) ---> Switch --> Mimosa radio pair -->Another router with BH taffic IP, VLAN for EPC bearer, and VLAN for EPC managment, with default route to Azotel WIB. EPC is plugged in to switch with bearer and management pointing to far router, and PDN VLAN pointing to WIB. If you can follow that, my question revolves around how the EPC uses ONE port to move all of it's traffic around, and if our traffic is actually going to where it's supposed to without having to double back. Say bearer traffic going to the WIB then to the EPC because of the default route at that far router. Or should all EPC VLANs terminate at the WIB? I ask mainly because we have seen some inconsistent speed tests, and when I do a traceroute to the EPC from that far router I get a failed hop in between the router and the EPC in the list of 3 hops (which I wouldn't expect to be 3 anyway). There is just some strangeness. Thanks, Tristan Johnson Owner [cid:emaf1d1023-ecda-4a6b-8eb3-033c355e09f8@maindesktop] www.wirelessdatanet.net<http://wirelessdatanet.net> 309-893-4152 ________________________________ [Avast logo]<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> This email has been checked for viruses by Avast antivirus software. www.avast.com<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> _______________________________________________ Telrad mailing list [email protected]<mailto:[email protected]> http://lists.wispa.org/mailman/listinfo/telrad
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