Latency on FTTC vs FTTP vs Leased line

I live quite far north in the country and ping times here are higher than the rest of the uk.

Pings to bbc.co.uk are 27ms on my home FTTC connection with Interleaving off.
On a leased fibre line at work, the ping time to bbc.co.uk is 17ms, 10ms faster.

My question is.. how much of that 10 ms of extra latency does the VDSL2 modem to modem part add to the connection, and how much is due to going through the Openreach backhaul? Once Openreach allows FTTPoD at my exchange/cabinet and I'm able to upgrade, would my latency decrease, and by how much?

Perhaps someone who is using FTTP and used to use VDSL/ADSL could comment?

Difficult to say for sure, we see around a 10 ms better latency on FTTH versus FTTC across the whole nation, but that is biased by so much of the FTTH being based in the South East (Gigaclear/Hyperoptic). Hard to say for FTTPoD as so few people with the GEA-FTTP product and difficult to spot as many just the entry level 40/80 Meg versions.

My FTTC just outside London gets 8-12 ms pings to London data centres. So I'd expect an improvement putting you in the 22-23 ms zone. Not worth the cost for FTTPoD unless a large trader.

Slightly higher than a leased line, since leased lines are more optimised, rather than sitting on a very large wholesale platform.

Average ADSL latency is around the 40ms region from the data I have.

Across two fairly fast areas, Ealing London we see 32ms average compared to 39ms from Edinburgh.

In reply to a post by Provster:

My question is.. how much of that 10 ms of extra latency does the VDSL2 modem to modem part add to the connection, and how much is due to going through the Openreach backhaul? Once Openreach allows FTTPoD at my exchange/cabinet and I'm able to upgrade, would my latency decrease, and by how much?

Perhaps someone who is using FTTP and used to use VDSL/ADSL could comment?

Remember a leased line has a guaranteed bandwidth assigned to it, so will usually have very low latency - It's also in the ISPs best interests.

Also every ISP and its customers can have different routing - the leased line will likely have a route which has likely been manually set up which goes through specific routers so they can guarantee bandwidth to the circuit - This can be optimized resulting in a lower ping. Residential connections' paths are usually dynamic.

As for the Openreach backhaul - It's fibre. It's likely BT's network routing which is adding the extra 10ms - Our connection at home's latency (FTTC) more than doubles after the 2nd hop due to poor routing.

I'd say at most around 1ms - The VDSL router/modem adding to the mix - it's a very good modem!

Your latency will definitely change with FTTPoD because it uses Fibre. Do a tracert and post the stats on here - We'll be able to give you an idea where the extra latency is coming from.

Not sure re: how much the latency will go down on a FTTPoD connection though because it's still through BTs horribly routed network (For some customers at least).

Theory would suggest that the difference between FTTC & FTTP on the same cabinet would only differ by a couple of millisecond at most. What I can say for sure is that, from where I ma (Maidenhead), I get an 8ms ping time to www.bbc.co.uk. Running tracert, the first node that doesn't time out using tracert is what looks like a BT handover point to a peering point whioch goes via Telehouse (in docklands). That's at 7ms. So the FTTC bit must be less than 7ms, but add in the delay in my router and the other two hops on the way that time-out on tracert, the bit added by FTTC is going to be low.

What this means is that the most important factor in the latency in you case will most probably be the routing by your ISP and not the technology by which you connect to the cabinet. I don't know if Andrew has information that breaks down latency from your region according to SP and (maybe) technology.

So it's going to be the choice of ISP that matters, and there's not guarantee which one is best on one day will always remain so. Also, choice may be illusory if many ISPs use the same wholesale networks.

So, if you have friends in the area with different ISPs, see what ping times they get.

FTTC;

PING www.bbc.net.uk (212.58.244.71): 56 data bytes
64 bytes from 212.58.244.71: icmp_seq=0 ttl=55 time=5.971 ms
64 bytes from 212.58.244.71: icmp_seq=1 ttl=55 time=5.855 ms
64 bytes from 212.58.244.71: icmp_seq=2 ttl=55 time=6.090 ms
64 bytes from 212.58.244.71: icmp_seq=3 ttl=55 time=5.943 ms
64 bytes from 212.58.244.71: icmp_seq=4 ttl=55 time=5.823 ms
64 bytes from 212.58.244.71: icmp_seq=5 ttl=55 time=6.105 ms
^C
--- www.bbc.net.uk ping statistics ---
6 packets transmitted, 6 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 5.823/5.965/6.105/0.106 ms

Connection: Inner London, Zen FTTC, 78968 down, 19999 up, Cisco 887VA-M-K9 router with no Openreach modem.

Where you are geographically located will certainly influence ping times. Routing will influence ping times. Your choice of ISP will change things. If your leased line has six hops to the Beeb and your home connection has nine that will make a difference. What do your traceroutes show?

The only real way to find out is to test with both leased line and FTTC/FTTPoD from the same ISP going to the same point of presence on their network to the same destination.

My home connection is terminated by Zen at Telehouse, London. Zen peers through LINX, which is based at Telehouse. That's where www.bbc.co.uk sits (at least from my location; the BBC may have DNS which resolves to different IP addresses depending on the source of the query). That's why it's fast for me.

If I was with a different ISP which didn't peer or connect at Telehouse but at another network centre, even in London, things would be slower.

When my connection went via Manchester due to maintenance on my local exchange, my ping to the Beeb was more than 25ms. If I ping from the router directly now it can be as low as 4ms;

coffee-gw#ping www.bbc.co.uk
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 212.58.244.66, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms

What I can say is that the VDSL2 modem to modem part of my connection cannot add any more than 4ms as that's what I can achieve pinging from the router all the way to www.bbc.co.uk.

Edited by caffn8me (Sat 18-Oct-14 01:13:30)

I think latency overhead on a FTTC line is almost 0 unless interleaving is applied.

The prime factor in latency is distance, so things like line routing affect latency.

Cool, thanks for that reply. My traceroute is as follows, it appears my first hop is Manchester which is 350 miles by road and it's 20ms. I suppose that's pretty decent.

Tracing route to bbc.co.uk [212.58.246.103]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms OpenWrt.lan [192.168.1.1]
2 21 ms 20 ms 20 ms losubs.subs.dsl6.wh-man.zen.net.uk [62.3.83.21]

3 20 ms 19 ms 19 ms no-dns-yet-62-3-86-41.zen.co.uk [62.3.86.41]
4 20 ms 20 ms 20 ms ge-2-0-0-0.cr1.wh-man.zen.net.uk [62.3.80.49]
5 27 ms 37 ms 27 ms ge-3-0-0-0.cr2.th-lon.zen.net.uk [62.3.80.45]
6 27 ms 26 ms 26 ms ge-2-0-0-0.cr1.th-lon.zen.net.uk [62.3.80.41]
7 27 ms 27 ms 27 ms rt-lonap-a.thdo.bbc.co.uk [5.57.80.90]
8 * * * Request timed out.
9 28 ms 31 ms 28 ms ae0.er02.cwwtf.bbc.co.uk [132.185.254.90]
10 29 ms 28 ms 29 ms 132.185.255.165
11 28 ms 28 ms 28 ms fmt-vip132.cwwtf.bbc.co.uk [212.58.246.103]

Trace complete.

That consistent 7ms loss transferring to zen-London at hop 6 looks a bit poor to me. But that's nothing to do with what product you are on, it's internal zen routing.

Two versions of tracert below. One using the IP address your DNS picked up, one using Plusnet DNS. I'm on Stepping Hill exchange a few miles south of Manchester. FTTC - sync speeds in my sig.

C:\Users\Bob>tracert 212.58.246.103

Tracing route to fmt-vip132.cwwtf.bbc.co.uk [212.58.246.103]
over a maximum of 30 hops:

1 5 ms 1 ms 1 ms 192.168.1.254
2 13 ms 21 ms 13 ms lo0-central10.ptn-ag01.plus.net [195.166.128.19]
3 13 ms 13 ms 13 ms link-a-central10.ptn-gw01.plus.net [212.159.2.18]
4 13 ms 20 ms 12 ms xe-5-2-0.ptw-cr01.plus.net [212.159.0.104]
5 13 ms 12 ms 13 ms kingston-gw.thdo.bbc.co.uk [212.58.239.6]
6 * * * Request timed out.
7 19 ms 14 ms 14 ms ae0.er02.cwwtf.bbc.co.uk [132.185.254.90]
8 14 ms 15 ms 14 ms 132.185.255.165
9 14 ms 14 ms 13 ms fmt-vip132.cwwtf.bbc.co.uk [212.58.246.103]

Trace complete.

C:\Users\Bob>tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.244.20]
over a maximum of 30 hops:

1 1 ms 1 ms 1 ms 192.168.1.254
2 13 ms 14 ms 14 ms lo0-central10.ptn-ag01.plus.net [195.166.128.19]
3 13 ms 13 ms 13 ms link-b-central10.ptn-gw02.plus.net [212.159.2.10]
4 18 ms 13 ms 12 ms xe-5-2-0.ptw-cr02.plus.net [212.159.0.106]
5 13 ms 12 ms 12 ms ae2.ptw-cr01.plus.net [195.166.129.4]
6 13 ms 13 ms 12 ms kingston-gw.thdo.bbc.co.uk [212.58.239.6]
7 * * * Request timed out.
8 * * * Request timed out.
9 15 ms 13 ms 13 ms ae0.er01.telhc.bbc.co.uk [132.185.254.109]
10 14 ms 13 ms 14 ms 132.185.255.149
11 13 ms 13 ms 20 ms fmt-vip71.telhc.bbc.co.uk [212.58.244.20]

Trace complete.

Edited by RobertoS (Mon 20-Oct-14 10:53:05)

I would have thought that the 7ms loss from Manchester to London was not too bad, it's 210 miles by road - but maybe it could be less?

My ping of 27ms to bbc.co.uk is the lowest I've seen up here, though when I was on Be Unlimited up here I think I was getting 23ms. I then got moved to Sky and my ping to BBC went up to 39ms.

London Level3 to Washington Level3 is adding 80ms for me .