![]() The over the air scheduler in the eNodeB is to respect the QoS rules to ensure traffic such as conversational-voice does not receive jitter/packet loss from background traffic (such as file transfer). This is taken to the level in LTE network's, where the LTE network depending on the rule will "Guarantee" the bitrate is available, and the rule is pushed to all aspects of the network include the eNodeB (Cell Site). The PCRF is capable of generating IP Source/Destination rules that are sent to the network, to prioritize the specific RTP conversation. In high level concept, when you use the IMS core to generate a SIP call, the local SIP proxies will have links back to the PCRF (policy server). routing/QoS rules that are rather nongranularĪctually, LTE has spent immense effort in providing capabilities and controls around prioritizing very specific traffic. I believe by convention, for roaming the "ims" APN is to be used, however, I'm having trouble locating the recommendation by either the GSMA or 3GPP, so now i'm not sure where I heard that.ģ. Is Verizon using separate APNs for their voice and data.īased on. It's up to the devices stack to use the proxy provided by the network, which as far as I'm aware no 3rd party software does at the moment.Ģ. IMS SIP proxy information is relayed to the device when it attached to the network if it's IMS capable. They assume all sip traffic must by their own, and route to their IMS Core I'll try and comment on some of the points you hit on.ġ. IMS/QOS on LTE is actually a very complicated topic, as it goes beyond routing/QoS rules. ![]() I think with Verizon having gone in with full knowledge of the restrictions involved, it's reasonable to hold them accountable. Verizon knew this restriction going in and could have chosen not to bid on that spectrum. Net neutrality isn't meant to be a suicide pact, but to be frank, almost all of the wireless spectrum that the FCC has made available for mobile doesn't carry this restriction. If the result is, "c'mon dude, you can't really expect us to do that," I don't have a lot of pity for it. It was auctioned with these restrictions with the idea that the restrictions are in the public interest and that it might cause the winner to undergo additional costs or lose certain pricing options. Without these restrictions, that spectrum may have raised more money. I'm sure people will forget about it," then it's kinda their own fault. I mean, at some point they have to have had meetings, "so, how will these open access rules affect our future?" And yea, I'm being a bit silly when I say "they have to have" (this is going to be a bit of a silly comment). Yeah.but to be a bit crass, that's totally Verizon's problem. It's savings are negligeable, and there's no end to the trouble it causes in operations. We explicitly avoided using the out-of-band audio feature, and we knew why. We didn't actually run IAX (mostly because the routers didn't support it), so I do not know much about it. And the upstream (towards providers) machines weren't even machines, but routers. The routing "cluster" needed to be 2 machines so as to be separate from the inbounds (due to much more complicated configs), and again 2 for redundancy in different datacenters (and then 4, and 8 when customer base grew). And the machines were needed anyway : inbound customer lines termination needed 2 machines for redundancy. How much ? Well, about 3*48 kbit per call, on a 10Gbe network. Yes this "wastes" bandwidth, both on the (internal) network and memory/cpu bandwidth too. I have managed a VOIP provider and at the edge we terminated SIP, terminated the audio on the incoming system, where it was sent to a central "cluster" for routing, and then terminated again on the outbound. I would argue however, that the "feature" of SIP to send the audio over an out-of-band channel has caused me so much misery over time that I wish it didn't exist. ![]() Obviously you don't want to run voice over a (real) TCP stream, so I got that wrong. ![]()
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