re: FTTH Technology Fracas Continues POTS interfaces will exist long after VoIP switches are ubiquitous.
Wait till you deal with the rural carriers who have things like Analog Loop Extenders, Firebar, Klaxon ringers (5 REN by the way), and all kinds of fun things. Get ready for Vidar switches.
re: FTTH Technology Fracas Continues"Those who choose G-PON are masking a conscious decision to be keeping legacy networks in place whilst having the option of passing ethernet traffic into a new metro ethernet network connecting to their new IP/MPLS cores. For GE-PON it has no TDM support thus straights ethernet." (spelling corrections implemented)
This isn't true. There are a lot of G-PON chips with Ethernet in, G-PON out, for both ends of the circuit. How the data is transported in the middle is really irrelevant (except that GPON transports Ethernet more efficiently than EPON). EPON isn't pure Ethernet--it also does TDM of the Ethernet streams on the receive side.
I always thought that this was the direction the telecoms were going anyway--that they had no plans for using the ATM features of GPON.
In my opinion GPON does better Ethernet transport than EPON. So those of you in the Ethernet preisthood should just back off and find some other devil to chase.
re: FTTH Technology Fracas Continues"Those who choose G-PON are masking a conscious decision to be keeping legacy networks in place whilst having the option of passing ethernet traffic into a new metro ethernet network connecting to their new IP/MPLS cores. For GE-PON it has no TDM support thus straights ethernet." (spelling corrections implemented)
This isn't true. There are a lot of G-PON chips with Ethernet in, G-PON out, for both ends of the circuit. How the data is transported in the middle is really irrelevant (except that GPON transports Ethernet more efficiently than EPON). EPON isn't pure Ethernet--it also does TDM of the Ethernet streams on the receive side.
I always thought that this was the direction the telecoms were going anyway--that they had no plans for using the ATM features of GPON.
In my opinion GPON does better Ethernet transport than EPON. So those of you in the Ethernet preisthood should just back off and find some other devil to chase.
I think that the previous reference was to the use of different GEM encapsulations and their use in GPON. You have brought up the fact that BPON, EPON and GPON are all TDM PONs in the way they share bandwidth upstream.
In terms of mapping efficiency, there is a lot of things that can be said about Bandwidth Allocation algorithms (both static and dynamic). GPON has a couple of tools that EPON does not, but in the end I think the gains their are probably more theoretical than practical.
In terms of practical efficiency, the difference in encoding, frame gaps, and overhead structures is the biggest difference. There GPON has a significant advantage (20% or so).
The humorous bit of all of this to me is that we are arguing about a few thousand gates on a Million Gate SOC at the ONT. The cost difference in this are basically negligible.
re: FTTH Technology Fracas Continues""Its frustrating too see the FTTx technologies languish in this country while we watch other countries pass us by. I hope some "catalyst" happens soon to break the stalemate""
Boy, I couldn't agree more. If VZ would have followed through on their intentions (promises?) to build out the edge back in the late 90's, we might not have had as severe of a telecom winter... perhaps none at all. You could argue that legislation was standing in their way ... but I won't go there.
Laying blame aside, I think it is time for the government to recognize that progress and prosperity are a linked concept, and if they are not willing to provide (at the very least) tax incentives for FTTP buildouts, then they bear the responsibility for a stalled economy.
Good grief, Bush thinks he can rejuvinate this economy by giving everyone $600? Not to be crude about it but if: 'it's the economy stupid' then surely it is "the infrastructure growth dummy!".
Wake up Washington. Growth for companies like Exxon are not going to send this country into the waiting arms of prosperity. Alternately, if you give companies like T and VZ incentives to build out our com infrastructure, it will be akin to the building of international highways after WWII (and we all know the resulting effects of that "infrastructure buildout").
re: FTTH Technology Fracas ContinuesI'd like to chime in and say that while many on this board seem to have a pretty deep lack of understanding of FTTx, brookseven really seems to know what he is talking about. He also seems to be free to share his knowlege.
And no, I am not his mom or anything. Just happy to see someone with an advised position on LR.
re: FTTH Technology Fracas ContinuesA couple of notes. I know Dynamic BW allocation [DBA] is possible on GPONs but I'm not sure it has ever been deployed because of system restraints [125us cycles make BW calculations difficult]. It has been widely deployed and developed on EPONs in Japan. The algorithms are quite comprehensive. Many things can be done at both the OLT and ONT to increase US efficiency. It is possible to get over 80% BW utilization US on a 1x32 PON using these algorithems. It is truly BW on demand as opposed to most fixed allocation systems on GPON deployments. As to Teras comment that GPON can tranfer Ethernet traffic more efficiently than an EPON.. well he/she is going to have to explain that one to me. EPON traffic is essentially Ethernet.. how can you tranfer data more efficiently than its native format ??
I concur with Jeff's post about BPONs DBA. The GPON RFP asked for support of both Status Reporting and non-Status Reporting DBA. The DBA implementation in EPON is similar to Status Reporting DBA.
Again, from my perspective the upstream scheduling can be shown to be very efficient in either GPON or EPON. However, GPON has a much more efficient optical layer than EPON.
I like what OldPOTS said, that a lot of this is more appearance and religion than technological differences.
re: FTTH Technology Fracas ContinuesDBA has been used for BPON at Verizon for a while now and will also be used for GPON should they ever get to volume deployments. There is no issue for implementation of status reporting or non-status reportding DBA related to processing power or anything like that.
For the puzzled few out there, DBA allows for oversubscription of the upstream 1.2 Gbps of bandwidth, even though it is TDM based. It allows a carrier to provision 10x or more bandwidth than actually available and have the PON ensure unused bandwidth is re-allocated from dormant or low use subscribers to active subscribers. It happens fast enough so that subscribers could never notice the transition. JB
POTS interfaces will exist long after VoIP switches are ubiquitous.
Wait till you deal with the rural carriers who have things like Analog Loop Extenders, Firebar, Klaxon ringers (5 REN by the way), and all kinds of fun things. Get ready for Vidar switches.
seven