Does anyone have any experience with a bridged APN on Open5GS?
David
Hi David,
On Mon, Apr 06, 2020 at 04:29:21PM -0400, david@ispsupplies.com wrote:
Does anyone have any experience with a bridged APN on Open5GS?
As far as I know, 3GPP didn't really introduce "Ethernet" type PDN contexts until very recent releases. For a long time, IPv4, IPv6 and IPv4v6 were the only available options.
I would be surprised if Open5GS supports non-IP PDN context types yet. But of course, it could be implemented in the pgw.
Out of curiousity: Is this a service you are already able to get from commercial / public mobile operators?
Regards, Harald
The Druid EPC supports it but it's pretty pricey. Most of the UE now support bridged APN but I don't know how exactly.
David Peterson Senior Engineer 855-947-7776 ext. 9214 c 419-706-7355 d 979-314-1305 https://www.ispsupplies.com
-----Original Message----- From: Harald Welte laforge@osmocom.org Sent: Tuesday, April 7, 2020 12:18 PM To: david@ispsupplies.com Cc: nextepc@lists.osmocom.org Subject: Re: Bridged APN
Hi David,
On Mon, Apr 06, 2020 at 04:29:21PM -0400, david@ispsupplies.com wrote:
Does anyone have any experience with a bridged APN on Open5GS?
As far as I know, 3GPP didn't really introduce "Ethernet" type PDN contexts until very recent releases. For a long time, IPv4, IPv6 and IPv4v6 were the only available options.
I would be surprised if Open5GS supports non-IP PDN context types yet. But of course, it could be implemented in the pgw.
Out of curiousity: Is this a service you are already able to get from commercial / public mobile operators?
Regards, Harald
Hi David,
On Tue, Apr 07, 2020 at 06:18:23PM +0200, Harald Welte wrote:
On Mon, Apr 06, 2020 at 04:29:21PM -0400, david@ispsupplies.com wrote:
Does anyone have any experience with a bridged APN on Open5GS?
As far as I know, 3GPP didn't really introduce "Ethernet" type PDN contexts until very recent releases. For a long time, IPv4, IPv6 and IPv4v6 were the only available options.
I just checked: Etehernet type PDN connections are only supported in 5G, but not in 4G/EPC. Even Releae 15 doesn't mention it at all.
So whatever some vendors may be offering, I would bet it is not really any actual Ethernet bridging. It may be more something like proxy-ARP on the PGW side, but still only passing IP over the 4G network.
The big question is: What is it used for, and what are the requirements of that use case? A real Ethernet bridge would be transparent regarding the MAC addresses on both sides. And that's what I'm stating is not possible over 4G as per 3GPP specs.
The reason this is something people want is that the UE in bridge mode can offer a public IP to a router behind the UE. I do agree that this is likely something very proprietary. A proxy-ARP would be good but I am not sure how that would work in the UE.
David Peterson Senior Engineer 855-947-7776 ext. 9214 c 419-706-7355 d 979-314-1305 https://www.ispsupplies.com
-----Original Message----- From: Harald Welte laforge@osmocom.org Sent: Tuesday, April 7, 2020 2:52 PM To: david@ispsupplies.com Cc: nextepc@lists.osmocom.org Subject: Re: Bridged APN
Hi David,
On Tue, Apr 07, 2020 at 06:18:23PM +0200, Harald Welte wrote:
On Mon, Apr 06, 2020 at 04:29:21PM -0400, david@ispsupplies.com wrote:
Does anyone have any experience with a bridged APN on Open5GS?
As far as I know, 3GPP didn't really introduce "Ethernet" type PDN contexts until very recent releases. For a long time, IPv4, IPv6 and IPv4v6 were the only available options.
I just checked: Etehernet type PDN connections are only supported in 5G, but not in 4G/EPC. Even Releae 15 doesn't mention it at all.
So whatever some vendors may be offering, I would bet it is not really any actual Ethernet bridging. It may be more something like proxy-ARP on the PGW side, but still only passing IP over the 4G network.
The big question is: What is it used for, and what are the requirements of that use case? A real Ethernet bridge would be transparent regarding the MAC addresses on both sides. And that's what I'm stating is not possible over 4G as per 3GPP specs.
Hi David,
On Tue, Apr 07, 2020 at 03:23:17PM -0400, david@ispsupplies.com wrote:
The reason this is something people want is that the UE in bridge mode can offer a public IP to a router behind the UE.
Normally I would have assumed that the router has a LTE modem/interface built-in, and hence the IP address of the PDP/PDN connection is local to the router.
If you want to implement a UE that doesn't terminate the IP of the PDP/PDN connection, I would argue that this is a feature that can be implemented entirely on the UE side, without any need from the network side.
Fundamentally, the point is that a 3GPP cellular network (before 5G) provides a point-to-point IP interface. There are no Ethernet frames, no MAC addresses, no broadcast domain, netmask, default gateway, etc.
A point-to-point interface only has a local and a remote IP address. Think of the good old days of SLIP/PPP over dialup modems.
Sure, you can invent all kinds of hacks like running a local DHCP server on the UE that hands out a single lease (which is the address allocated by the P-GW/GGSN), but they are probably even more ugly hacks than to implement stateless bi-directional 1:1 address translation in the UE.
In any case, I still don't see what the EPC could or should do in any of this.
Regards, Harald
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david＠ispsupplies.com -
Harald Welte