TK Junk Mail
Go ahead, make my day
Premium
join:2002-03-03
Margate City, NJ
clubs:
 ·Comcast
|  How to tell max # of customers allowed on your local node
While researching something, I came across a way to determine what the maximum number of users could be on your local node.
And that is the subnet mask that Comcast assigns to the IP address given you when you connect. I find mine in my Netgear router under "router status". Your location will depend on what router, if any, you are using.
Here is my IP subnet mask:
IP Subnet Mask 255.255.248.0
The value of that mask determines the maximum number of customers that can be connected to that node. Of course, there can be FEWER customers, but not more.
»articles.techrepublic.com.com/51···906.html
My subnet mask says that I could have up to 2046 users on my local node. Since I am very fast without any delays even in prime time hours, I suspect my node doesn't have near the max users allowed.
Does anyone here have fewer hosts allowed on their node than 2046?
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tdumaine
join:2004-03-14
Redmond, WA | Subnet Mask: 255.255.254.0
So by your chart, 510 |
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gdm
Premium,MVM
join:2001-06-15
Mchenry, IL
clubs: | Same for me 255.255.254.0. I have never seen a delay no matter the hour. |
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kaiser
join:2005-08-01
Burlington, VT | reply to tdumaine
255.255.248.0....so 2046... |
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Rob
In Deo speramus
Premium
join:2001-08-25
Kendall, FL | reply to TK Junk Mail
Mine is 255.255.248.0, so 2046 # of hosts. |
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DMS1
join:2005-04-06
Carrollton, TX
| reply to TK Junk Mail
said by TK Junk Mail  :The value of that mask determines the maximum number of customers that can be connected to that node. Of course, there can be FEWER customers, but not more. Whilst what you say is not wrong, I'm not sure this provides a useful indication of node loading. It all depends on how religious they are at setting the subnet mask to the minimum possible for the node. Since a couple of people have already reported a value of 2046, I suspect the answer is "not very". |
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deblin
Dark Side of the Moon
Premium,MVM
join:2001-09-01
Middletown, DE
 ·Verizon FIOS
·Comcast Workplace
 ·DSL EXTREME
| said by DMS1 :Whilst what you say is not wrong, I'm not sure this provides a useful indication of node loading. It all depends on how religious they are at setting the subnet mask to the minimum possible for the node. Since a couple of people have already reported a value of 2046, I suspect the answer is "not very". Precisely, and I'm no expert on the topology and architecture of cable networks, but just because you have a particular netmask doesn't mean they are not segmenting it further and multiple nodes are serving the same subnet.
A better way might be to listen to ARP traffic and see how many hosts, over time, are asking for the gateway on your subnet. Granted, not everyone keeps their router/computer on 24/7, but if you let it run for a few days you'd probably have a nice unique list of MAC addresses (and hence # of people on your broadcast segment).
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Qumahlin
Never Enough Time
Premium,MVM
join:2001-10-05
West Chester, PA
| reply to TK Junk Mail
Sorry, doesn't work this way, it will be right in some situations, but in most, especially any high density urban area you won't come close.
This goes back to the whole misunderstanding of node vs line card vs ports
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jbob
Reach Out and Touch Someone
Premium
join:2004-04-26
Little Rock, AR
·Comcast
·AT&T Southwest
edit:
August 7th, @03:53PM
| said by Qumahlin :Sorry, doesn't work this way, it will be right in some situations, but in most, especially any high density urban area you won't come close. This goes back to the whole misunderstanding of node vs line card vs ports Thanks Qumahlin That seems like a reasonable explanation.
I do remember seeing a link to a way to possibly determine how many users are on your node/card but I didn't pursue it when I first saw it and now can't find that info anymore. I can't say now whether it might have been talking about active users or subscribed users.
Edit= grammar |
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quetwo
That VoIP Guy
Premium
join:2004-09-04
East Lansing, MI
·TDS
| reply to TK Junk Mail
Networking can become much more complex then just figuring out the subnet. When Comcast owns entire swaths of IP landscape, they can do some creative routing if they want to.
For example, on our campus, we have a 255.0.0.0 subnet, because we own 35.0.0.0/8. However, we have routers that know and respect ARP, can transport and filter traffic properly using advanced routing techniques. (We do this, for example, because every device/student is assigned an IP address, and it dosen't matter which of the 660 buildings they plug into).
Also, as stated earlier, subnets don't have any correlation between node side, and subnet size. Subnets typically let you distinguish between what is on your side of the router (local network), and what needs to be sent to the router for external traffic. A router =/= cable headend or node. |
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odog
Cable Centric Vendor Biased
Premium
join:2001-08-05
Norcross, GA
clubs:
·Metrocast Communic..
·Comcast
 ·Vonage
| reply to Qumahlin
said by Qumahlin :Sorry, doesn't work this way, it will be right in some situations, but in most, especially any high density urban area you won't come close. This goes back to the whole misunderstanding of node vs line card vs ports Subnets mean nothing to modems on the node, or modems on the upstream port, or the modems downstream.
Let me say it again NOTHING! |
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smcallah
join:2004-08-05
Home
| reply to TK Junk Mail
Knowing the size of the subnet that you are in will not tell you how many modems can be on your node.
Nodes don't have IP's. Nodes are basically fiber to coax devices near your house where you neighborhood is aggregated. This node is carried back over the fiber to the local hub you are connected to, where it connects to a CMTS of some type.
This CMTS most likely is a router also, which could have tens to hundreds of nodes on it.
Also, there would be more than 1 subnet assigned to the entire CMTS. I've seen next door neighbors in totally different subnets, and obviously, they're on the same node. |
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TK Junk Mail
Go ahead, make my day
Premium
join:2002-03-03
Margate City, NJ
clubs:
·Comcast
| said by smcallah :Knowing the size of the subnet that you are in will not tell you how many modems can be on your node. Nodes don't have IP's. Nodes are basically fiber to coax devices near your house where you neighborhood is aggregated. This node is carried back over the fiber to the local hub you are connected to, where it connects to a CMTS of some type. This CMTS most likely is a router also, which could have tens to hundreds of nodes on it. Also, there would be more than 1 subnet assigned to the entire CMTS. I've seen next door neighbors in totally different subnets, and obviously, they're on the same node. Then I should be good. Because the node in my neighborhood can only service about 200 homes, because that is all there is before the next development which is a mile or so away.
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major marco
Res Firma Mitescere Nescit
Premium
join:2003-02-13
Mission Viejo, CA
clubs:
| Don't be such freakin' naive. What makes you think that your ISP would ever, under any circumstances, ever reveal to subscribers precisely how many other subscribers they cram onto any given node? That would be like admitting they're skimping on infrastructure to fatten their bottom lines and they're just not EVER going to admit such a thing to their paying customers. |
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CableTool
Poorly Representing MYSELF.
Premium
join:2004-11-12
| said by major marco :Don't be such freakin' naive. What makes you think that your ISP would ever, under any circumstances, ever reveal to subscribers precisely how many other subscribers they cram onto any given node? That would be like admitting they're skimping on infrastructure to fatten their bottom lines and they're just not EVER going to admit such a thing to their paying customers. There is no cover up. I see penetration everyday.
When anything gets near capacity there is a PO put in for a node split, segmentation, new router, whatever is needed. Now it might take a minute to get that PO approved.. but there are ENTIRE DEPARTMENTS dedicated to capacity. And their goal isnt to get as many customers crammed onto a channel as possible, its to provide a certain QOS.
Regions areas and budgets will vary across the country, but their common goal is a working and effecient network.
Dont be so freaking paranoid and cynical. 
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CableFAQ.org/Technicians Unplugged
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plat2on1
join:2002-08-21
Hopewell Junction, NY
clubs:
| reply to major marco
said by major marco :Don't be such freakin' naive. What makes you think that your ISP would ever, under any circumstances, ever reveal to subscribers precisely how many other subscribers they cram onto any given node? That would be like admitting they're skimping on infrastructure to fatten their bottom lines and they're just not EVER going to admit such a thing to their paying customers. you could just call and ask, last time i had an outage i asked if they could check if any other modems where offline and the rep had no problem telling me only 5 of the 125 were offline. |
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rednekbrh
join:2005-10-14
Mason City, IA
·Mediacom
| reply to TK Junk Mail
Actually you could be completely off the mark a subnet mask means nothing with out knowing if you are on a class a b or c network for example my ip address is on a class a meaning that there are 24 bits available to borrow which greatly increases the number of networks and users greatly increases with the sub-nets you list. also with classless addressing you really can never know for sure how many sub-nets or users are available. and on top of everything else there are other ways around this. so in conclusion even if you look at your ip and your subnet is a subnet has no meaning without knowing what ip class you are you really have know way of knowing how many users are on your node. |
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smcallah
join:2004-08-05
Home
| for example my ip address is on a class a meaning that there are 24 bits available to borrow which greatly increases the number of networks and users greatly increases with the sub-nets you list.
Classes don't mean anything anymore. There is lots of former "Class A" space being assigned out to ISP's now. And they are not being assigned as the entire "Class A" or /8 as it should be known.
There is no ISP that does Classful routing, unless they happen to own an actual old Class A, Class B, or Class C. And in either case, they're still doing Classless routing, since they have likely broken up the Class A's and Class B's into many smaller CIDR blocks to route over their networks.
Your IP being in a "Class A" doesn't mean there are 24 bits available for a host in the network you're on, your ISP has a certain CIDR block assigned out of what was formerly a "Class A."
I really do wish "networking" classes would stop teaching Class A, B, and C as if they're still in use. It is a nice history lesson and it is good to understand what it was, but they have had no bearing on Internet routing for the last 10 years at least. |
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ztmike
Premium
join:2001-08-02 | reply to TK Junk Mail
255.255.255.0 so 254 hosts |
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wee96
Your Local Confederate
join:2000-04-12
Clinton Township, MI | reply to TK Junk Mail
This thread has me dying laughing, especially your comment about "penetration" CT  |
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