dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
12
share rss forum feed


wmcbrine
213 251 145 96

join:2002-12-30
Laurel, MD
kudos:1
reply to navyson

Re: FIOS internet - how much faster can FIOS get?

I see no reason they couldn't offer gigabit. It would just be shared. But that's how cable is anyway.
--
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0


ITALIAN926

join:2003-08-16
kudos:2
Reviews:
·Verizon FiOS
With GPON having to share 2.4Gbps among 16 or 32 customers, I doubt very much they will offer that much individual speed. Simply upgrading to the next PON will obviously answer that "problem" Perhaps 10 Gbps (oc192) shared on the PON cards? Maybe theyll go straight to 39 Gbps (oc768) ?? That would be cool.

Besides that, is Comcast REALLY matching? Theres a helluva lot of restrictions on someone getting that tier from Comcast, including a $500 install fee?

brianiscool

join:2000-08-16
Miami, FL
kudos:1
reply to wmcbrine
Wow, that is a lot of bandwidth. I thought when I was using my 153Mbps I was knocking everyone off in my area. LOL

Sammer

join:2005-12-22
Canonsburg, PA
reply to ITALIAN926
said by ITALIAN926:

With GPON having to share 2.4Gbps among 16 or 32 customers, I doubt very much they will offer that much individual speed.

GPON can be up to 1 Gbps symmetrical but yes it would be overbooked if 16 users all used that at exactly the same time.


bigdaddy

join:2009-11-18
kudos:2
said by Sammer:

said by ITALIAN926:

With GPON having to share 2.4Gbps among 16 or 32 customers, I doubt very much they will offer that much individual speed.

GPON can be up to 1 Gbps symmetrical but yes it would be overbooked if 16 users all used that at exactly the same time.

So GPON's Max Upload Speed potential 1.244 Gbps split 32 way's is 38.875Mpbs. So how can VZ offer 65Mpbs Upload over GPON via the 150/65 and 300/65 Tiers isn't that a Recipe for Over Subscription ? Now XG-PON has a Max Upload Speed of 2.5Gbps split that 32 way's you come out with 78.125Mbps per user. Why doesn't VZ roll out XG-PON for the FiOS Quantum Tiers ?

Same go's for Down Speed GPON 2.448Gbps split 32 way's is 77.75Mbps. XG-PON split 32 way's is 312.5Mbps. The FiOS Quantum 300/65 should be on XG-PON Not GPON. So how in the World is VZ FiOS Going to offer 500/65 ? Like I said a Recipe for Over Subscription.


ITALIAN926

join:2003-08-16
kudos:2
Reviews:
·Verizon FiOS

1 edit
What % of people do you think are uploading more than 35Mbps at any given moment? The only people eating this bandwidth constantly are the copyright infringers, and fortunately, the majority of people in this country still follow the laws.

You dont think this company can monitor usage for the entire PON? come on now.

... and by the way, Netflix uses up the most bandwidth on the net, Max 5Mbps per user. If every Verizon customer was streaming netflix all at the same time, it would have zero impact on their PONS, even BPON.

McBane

join:2008-08-22
Plano, TX
It really depends on the area you live. When I lived on a college apartment complex that had FiOS when it first came out we maxed the BPON upload constantly, and this was back when 25 up was the max. Guess what? It was pretty much all copyright infringers. If you live in an area with a lot of high tech or IT workers your going to see that problem dramatically increase. Now we have Netflix and streaming services so it helps alleviate the problem, though. This was back in '06 through '09 when I lived in those apartments.


Active Opto

@lstn.net
reply to bigdaddy
said by bigdaddy:

So GPON's Max Upload Speed potential 1.244 Gbps split 32 way's is 38.875Mpbs. So how can VZ offer 65Mpbs Upload over GPON via the 150/65 and 300/65 Tiers isn't that a Recipe for Over Subscription ? Now XG-PON has a Max Upload Speed of 2.5Gbps split that 32 way's you come out with 78.125Mbps per user. Why doesn't VZ roll out XG-PON for the FiOS Quantum Tiers ?

Same go's for Down Speed GPON 2.448Gbps split 32 way's is 77.75Mbps. XG-PON split 32 way's is 312.5Mbps. The FiOS Quantum 300/65 should be on XG-PON Not GPON. So how in the World is VZ FiOS Going to offer 500/65 ? Like I said a Recipe for Over Subscription.

Contention and split ratios are the least worrisome point for passive optical networks(GPON and 10G XG-PON) on last mile connections.
They can be planned carefully from the start to limit the number per port according to how much bandwidth the operator intends to sell.
However it doesn't make much sense to go with very low contention with passive networks (1:8 or 1:4), instead operators prefer to do it with P2P since it does not justify for much cost savings to do so.

The 2 major concerns with GPON/XG-PON instead are:

1) How are you going to feed the monster OLT box backplane connection that connects it back to the core aggregation switches.

2) How to tame monster OLT box with the high number of connections and traffic it has to handle as subscriber rate scales to peak numbers. It requires a monster processing power to handle thousands of simultaneous users compared to dedicated ports for active Ethernet users?If each subscriber creates >64 connections, it's enough to cause massive congestion, thus causing huge spikes in latencies during peak hours.

Just to compare, this is one of the highest capacity and latest OLT product from Calix.[Note: Current present GPON OLTs on average only handles about 200Gbps for backplane connections]
»www.calix.com/systems/e-series/c···-20.html

Key highlights to note(quoted from site):
-2 terabit backplane with 100 Gbps connection to each line card slot
-Serves 480 point-to-point GE or over 10,000 GPON subscribers, with the capacity to serve over 20,000 subscribers through higher density line cards in the future

So if you just do a simple calculation:
The latest GPON/XG-PON line cards have 8 ports today.
Assume they are selling a 1Gbps service.
If each card has ONLY a 100gbps to breath, while each port handles 30 lines(32 in theory with 2 often reserved) on a passive splitter,
8 x 32 lines/ONTs x 1Gbps = 256Gbps diet
[Compare this again to active ethernet, 480ports/20 line cards you get only around 24 ports to share the 100Gbps load on each line card - That'a nearly 10x more capacity for each line card (256/24)]
*Important note: In reality, many ISPs are only giving 1x-4x 10GE Ethernet lines to their OLTs backplane. Complains are already coming in mostly during peak hours.

Next comes switching speed and connection load handling between users. Cisco claims they can handle terabit speeds with their active switches with at most only caters around 400 dedicated ports , but how about a high capacity OLT that claims to handle 10k to 20k users simultaneously? That's quite a monster to tame.

McBane

join:2008-08-22
Plano, TX
FiOS, it sucks less than cable. You just have to rationalize it even though it's the same problems on fiber instead of coax.


mig288
Premium
join:2002-07-13
Cherry Hill, NJ
please elaborate? what "problems" are you referring to?
Expand your moderator at work

McBane

join:2008-08-22
Plano, TX
reply to mig288

Re: FIOS internet - how much faster can FIOS get?

said by mig288:

please elaborate? what "problems" are you referring to?

I think bigdaddy and Active Opto lay it out pretty well and in some areas it is already over congested. I used to live in one of those areas so I know.

batsona
Maryland

join:2004-04-17
Ellicott City, MD
Reviews:
·Vonage
·Verizon FiOS
reply to Active Opto
Active Opto: I never thought of it that way. Given how different ethernet is, from Passive Optical on layer 1 & layer 2, there must be alot of CPU thats chewed up in aggregating 10's of thousands of layer-2 conversations on the OLT, into just a few layer-2 connections when everything is aggregated onto a core Internet router. Depending on what you're doing, it takes alot of CPU to fool around at layer2.

So, the over-subscription is not neccessarily related to bandwidth, but also the ability of the devices that take 10,000 conversations across multiple layer-1 cables, and put them onto 2-3 connections to an aggregation router.

buckweet1980

join:2011-12-31
Allen, TX
said by batsona:

Active Opto: I never thought of it that way. Given how different ethernet is, from Passive Optical on layer 1 & layer 2, there must be alot of CPU thats chewed up in aggregating 10's of thousands of layer-2 conversations on the OLT, into just a few layer-2 connections when everything is aggregated onto a core Internet router. Depending on what you're doing, it takes alot of CPU to fool around at layer2.

So, the over-subscription is not neccessarily related to bandwidth, but also the ability of the devices that take 10,000 conversations across multiple layer-1 cables, and put them onto 2-3 connections to an aggregation router.

You'd be surprised what a network device can do when it's tasks are implemented on ASICs, they allow for very little traditional CPU to be required. With network switches and high end routers all of the functions needed to service the network are handled via the line card ASICS and rarely ever punted to the device CPU. Typically the only time traffic is punted to the CPU is for control plane traffic.

In the FIOS use case the OLT devices are really nothing more than a bridge/transceiver to get the traffic off of the GPON medium and onto Ethernet at the CO. It doesn't really care about the layer-2 conversations, it just processes them transparently. The real work on FIOS is being done by the routers sitting behind the OLT boxes. FIOS for my node is serviced by a Juniper E series router, which I assume is common across most areas. The E series have been around for a long time and are specifically built for handling 10's of thousands of subscribers on a single box.

Traditional PC/Server computing rules don't apply to devices built specifically for these tasks in terms of traffic forwarding.

McBane

join:2008-08-22
Plano, TX
Yeah the connections per second are nothing for an OLT router or any time of backbone or provider router to handle. That is what network specific hardware is built for. The limiting factor is going to be all about the bandwidth available, on both sides of the OLT.

From my experience though Verizon has got the hang of managing and balancing the FiOS network pretty well. Originally back in '06 - '08 they absolutely sucked at managing it, though. Verizon also doesn't seem to have a problem at expanding capacity where needed as soon as possble compared to any other ISP I've ever had. Luckily their Network Engineers learn from their mistakes unlike some other providers, like most of the cable companies...

I just wish their customer service and billing departments were just as good.


Active Opto

@lstn.net
reply to buckweet1980
said by buckweet1980:

In the FIOS use case the OLT devices are really nothing more than a bridge/transceiver to get the traffic off of the GPON medium and onto Ethernet at the CO. It doesn't really care about the layer-2 conversations, it just processes them transparently. The real work on FIOS is being done by the routers sitting behind the OLT boxes. FIOS for my node is serviced by a Juniper E series router, which I assume is common across most areas. The E series have been around for a long time and are specifically built for handling 10's of thousands of subscribers on a single box.

Not as transparent as what GPON vendors want buyers to believe. The OLT still has to maintain a very long list of MAC addressing table and ONT IDs. It also have to continuously identify/monitor for ONTs for bandwidth mapping, time all the slots accordingly and GEM packaging for the 10s of thousands capacity which the vendors claim. I find them a little exaggerating. The OLT also has the ability to isolate VLANs with transmission containers(T-Conts)and places traffic prioritization on them. That's one way how they do garden walled IPTV services like FIOD TV.

No doubt many call the OLT a dumb Layer 1 switch that has most of the upper layers taken care of by the core routers such as IP routing, but there are some tasks which is unique to the OLT.

quote:
The real work on FIOS is being done by the routers sitting behind the OLT boxes.

This is the 2nd weakness of the GPON OLTs I pointed out earlier. The model itself is best suited to serve high density populated areas with many lines per port (>30 splits per port) to maintain its competitiveness against active switches. Now here's the catch: You buy a very expensive OLT set that claims to cater for 10s of thousands of ONTs after receiving all the demand from the locals. But your backplane of your OLT only takes in multiple 1GE, 10GE and 100GE at most.
How do you intend to keep up with the growing demand?

The key point is to learn from the cable industry where they too had faced this very same problem with the headends not keeping up with the rate cable modems installations. Many started complaining of slowdowns during peak hours and they are not getting close to their subscribed speeds.

Eventually they learn from their mistakes and solved the issue by creating more "mini nodes" to spread things out more evenly by means of effective rationalizing.

In the case of passive networks the same move can be done by increasing more OLT ports, buying more miniaturized OLTs and decreasing split ratios. But before you do that, don't you think the architecture of active switches were better suited for such situations? You are better organized and ready to serve with packages beyond 1gbps with dedicated active ports than you do with passive networks.Would you buy an expensive cabinet sized OLTs just to do few hundred lines? Better spend your extra on the core routing and transport.

I can count my dedicated active ports better with a 10GE than an expensive OLT with a single GPON line card with many logical connections over shared lines.

A monster still needs a matching digestive tract to suit its appetite.

We have to consider our options resonably that 1GE and 10GE are the only mainstream options for uplinks. 100GE is ready but equipments are still expensive. Why would you spent on a big box that claims a capacity which its backhaul can't keep up?

Fiber is not an issue with economics of scale. It's going to get cheaper since silica is plenty to be found in the ground. Manufacturing process improvements will only lower manufacturing cost over time till it becomes cheaper than copper one day. For new ISPs building new infrastructures, it's best they keep solely to Ethernet to simplify their setup. TDM and ATM should be phased out entirely for modern NGNs.With IPTV, very few service providers are using the RF overlay option for their cable tv services.

buckweet1980

join:2011-12-31
Allen, TX

1 edit
Yeah you said something I've been very shocked to find out when researching OLTs (for my education).. I work for a large networking manufacturer, mainly for the enterprise markets. One of the first thing's we always get asked about is over-subscription rates, so naturally that is the first thing I look for when looking at these boxes.

I see tons of ports out, but very few Gig/TenGig in. Some of these manufacturers have 4 ports or more per card. With that I'd expect a 10gig interface for the uplinks. Over-subscription must be very high when factoring in that we're being split 16/32/64 times in the field and then it's being subscribed even much higher at OLT level. My connection (150mb) doesn't ever to seem to have bandwidth issues currently, but I'm sure the day will come when it does..