|
|
|
|
| Author |
Message |
w_tom
Guest
|
 Posted: Wed May 09, 2007 7:59 am Post subject: Re: Help needed with intermittent internet |
 |
|
On May 8, 12:09 am, "JM" <jakem38671omitt...@yahoo.com> wrote:
| Quote: | The heart of the question, as far as I'm concerned. Comcast has suggested
that the activities of our mail server is causing the problems. And I
continue to repeat your question: What bearing does content and traffic in
general have on the performance (or lack thereof) of a cable modem????
|
Looking at what some Netgear modems report. They don't report
signal to noise ratios - therefore Comcast remote centers may have no
such data contrary to what others have implied. These modems do
report a count of packets transmitted and received along with another
important number - data that counter is reset. Therefore if e-mail
was causing a problem, then number of packets transmitted would be
excessive and obvious.
These are numbers that a tech could provide if he has them. But
again, important numbers that might show a problem are still unknown
because numbers are not being provided AND what the tech uses to say
problem does not exist - both are unknown.
There is no acceptable reason why status information is denied the
subscriber.
Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.
Also not defined is whether modem is in router mode or bridge mode. |
|
| Back to top |
|
 |
Fix your Windows Problems - FAST.
FREE Safe Scan Registry Check. Locate & Fix Errors in Minutes!
|
|
Warren H
Guest
|
| Posted: Wed May 09, 2007 10:34 am Post subject: Re: Help needed with intermittent internet |
|
|
w_tom wrote:
| Quote: | Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.
|
He's using the server as his LAN router. The Netgear router isn't
routing in the lay sense of the word. That is, in the topography of his
network, it's not directing traffic here or there. It is only sitting
there between his server (which is the real router on his LAN), and the
cable modem, but it's opening packets, and repackaging them as a router
does, and not simply passing them through as a bridge would.
| Quote: | Also not defined is whether modem is in router mode or bridge mode.
|
I can't find a model number for the piece of equipment, but giving this
more consideration, I don't think it can actually be configured to be a
bridge. I believe that it can only act as a router. It can act as a NAT
router, or it can operate as a normal router. Not normal in the same
since as a "home" or "broadband" router, which normally acts as a NAT
router, but normal as in it routes packets to various public IP
addresses. In this case, there's only one IP address to route to, but
that doesn't mean the equipment stops opening packets like a router
does, and turns into a bridge that doesn't open packets. (Remember that
a router and a bridge operate on different levels of the OSI model.)
Also, if it were just a bridge, there's no ISP that's going to waste a
publicly routable IP address on it. As a bridge, it's IP address would
only be useful for managing the equipment, and would not be a part of
the path through the device. For that, they'd use a private range IP
address just like they do for the cable modem.
The more I think about this issue, assuming that everyone is reporting
honestly, my confidence that it's not the cable modem, and that the
failure is happening because something is crashing the router part of
the Netgear box goes up.
--
Warren H.
==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker |
|
| Back to top |
|
|
$Bill
Guest
|
| Posted: Wed May 09, 2007 11:21 am Post subject: Re: Help needed with intermittent internet |
|
|
w_tom wrote:
| Quote: |
These are numbers that a tech could provide if he has them. But
again, important numbers that might show a problem are still unknown
because numbers are not being provided AND what the tech uses to say
problem does not exist - both are unknown.
There is no acceptable reason why status information is denied the
subscriber.
|
True.
| Quote: | Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.
|
There's a switch in there and another router now, so that shouldn't
be happening. There may also be a switch on the Netgear ????
Still don't know the model. |
|
| Back to top |
|
|
Warren H
Guest
|
| Posted: Wed May 09, 2007 12:11 pm Post subject: Re: Help needed with intermittent internet |
|
|
$Bill wrote:
| Quote: | There may also be a switch on the Netgear ????
|
Right. If there's more than one Ethernet port, there would be a switch
involved. But a switch operates on an even lower-level than a bridge, so
the chances that it's a switch issue is low. And since the most likely
switch-related issue would be the physical hardware, since three
different Netgear boxes have been used, it's not likely that they all
had the same physical defect.
--
Warren H.
==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker |
|
| Back to top |
|
|
$Bill
Guest
|
| Posted: Wed May 09, 2007 2:39 pm Post subject: Re: Help needed with intermittent internet |
|
|
Warren H wrote:
| Quote: | $Bill wrote:
There may also be a switch on the Netgear ????
Right. If there's more than one Ethernet port, there would be a switch
involved. But a switch operates on an even lower-level than a bridge, so
the chances that it's a switch issue is low. And since the most likely
switch-related issue would be the physical hardware, since three
different Netgear boxes have been used, it's not likely that they all
had the same physical defect.
|
I was referring to the fact that if there is a switch, the packets from
the LAN may not even make it to the router portion. Therefore, no local
LAN pinging problem could exist. And we know there's another switch farther
in that should allow the local PCs to ping each other without a router
getting involved. This in response to Tom's pinging stmt. |
|
| Back to top |
|
|
Fix your Windows Problems - FAST.
FREE Safe Scan Registry Check. Locate & Fix Errors in Minutes!
|
|
JM
Guest
|
| Posted: Wed May 09, 2007 7:41 pm Post subject: Re: Help needed with intermittent internet |
|
|
I'm not sure where to put my responses now.
I just want to thank everyone for their time and effort. I sincerely
appreciate it. Really. I'd be totally on my own without this discussion.
| Quote: | Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.
He's using the server as his LAN router. The Netgear router isn't routing
in the lay sense of the word. That is, in the topography of his network,
it's not directing traffic here or there. It is only sitting there between
his server (which is the real router on his LAN), and the cable modem, but
it's opening packets, and repackaging them as a router does, and not
simply passing them through as a bridge would.
|
Correct, with the addition of a Linksys WRT54GL between the LAN switch and
Netgear.
| Quote: | Also not defined is whether modem is in router mode or bridge mode.
I can't find a model number for the piece of equipment,
|
It's a Netgear CG814CCR v2. I'm sorry. I thought I provided this a long
time ago, but I did not.
| Quote: | but giving this more consideration, I don't think it can actually be
configured to be a bridge. I believe that it can only act as a router. It
can act as a NAT router, or it can operate as a normal router. Not normal
in the same since as a "home" or "broadband" router, which normally acts as
a NAT router, but normal as in it routes packets to various public IP
addresses.
|
This is how I understand it.
| Quote: | In this case, there's only one IP address to route to, but that doesn't
mean the equipment stops opening packets like a router does, and turns into
a bridge that doesn't open packets. (Remember that a router and a bridge
operate on different levels of the OSI model.)
Also, if it were just a bridge, there's no ISP that's going to waste a
publicly routable IP address on it. As a bridge, it's IP address would
only be useful for managing the equipment, and would not be a part of the
path through the device. For that, they'd use a private range IP address
just like they do for the cable modem.
|
That's correct. There is no bridge mode in play here at all. That was a
terminology error on my part.
| Quote: | The more I think about this issue, assuming that everyone is reporting
honestly, my confidence that it's not the cable modem, and that the
failure is happening because something is crashing the router part of the
Netgear box goes up.
|
I've been 100% honest, although I can't say for sure I've reported 100% of
the pertinent information. I've done my best, but I've spent a tremendous
amount of time with this issue. If I'm leaving something important out,
it's simple oversight.
As for events since I posted last: Last night I logged into the Linksys and
disabled outbound traffic from the server. I put a 24/7 block on the
server's internet NIC. This morning at 7:50 the Netgear was unresponsive to
ping from my office.
To me, this is compelling information, although I'm not sure how to
interpret it. Does this demonstrate definitively that outbound server
traffic is not the root cause? Did my block indeed prevent all packets from
reaching the Netgear? I seems so. Am I missing something?
Next I want to completely turn the server off for the night. This takes
some doing, because we back up data at night, and I do not have complete
access to the building. But I can arrange it.
Then, depending on the results, I want to disconnect everything from the
Netgear except one clean PC.
I'm not sure what else to try.
Also, what information exactly should I request from Comcast? A text file
containing the router logs?
jm |
|
| Back to top |
|
|
JM
Guest
|
| Posted: Wed May 09, 2007 7:43 pm Post subject: Re: Help needed with intermittent internet |
|
|
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:46416863$0$9902$4c368faf@roadrunner.com...
| Quote: | w_tom wrote:
These are numbers that a tech could provide if he has them. But
again, important numbers that might show a problem are still unknown
because numbers are not being provided AND what the tech uses to say
problem does not exist - both are unknown.
There is no acceptable reason why status information is denied the
subscriber.
True.
|
What exactly should I ask for? I will gladly go back to them. When I've
asked for this type of information before they are not sure what to give me.
| Quote: | Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.
There's a switch in there and another router now, so that shouldn't
be happening. There may also be a switch on the Netgear ????
Still don't know the model.
|
I apologize. It is a Netgear CG814CCR v2
jm |
|
| Back to top |
|
|
JM
Guest
|
| Posted: Wed May 09, 2007 7:45 pm Post subject: Re: Help needed with intermittent internet |
|
|
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:4641a5bd$0$1416$4c368faf@roadrunner.com...
| Quote: | Warren H wrote:
$Bill wrote:
There may also be a switch on the Netgear ????
Right. If there's more than one Ethernet port, there would be a switch
involved. But a switch operates on an even lower-level than a bridge, so
the chances that it's a switch issue is low. And since the most likely
switch-related issue would be the physical hardware, since three
different Netgear boxes have been used, it's not likely that they all had
the same physical defect.
I was referring to the fact that if there is a switch, the packets from
the LAN may not even make it to the router portion. Therefore, no local
LAN pinging problem could exist. And we know there's another switch
farther
in that should allow the local PCs to ping each other without a router
getting involved. This in response to Tom's pinging stmt.
|
When the Netgear (model CG814CCR v2) is down (unresponsive, locked up, no
internet, etc), all internal network functions work fine.
jm |
|
| Back to top |
|
|
Warren H
Guest
|
| Posted: Thu May 10, 2007 1:07 am Post subject: Re: Help needed with intermittent internet |
|
|
JM wrote:
| Quote: | As for events since I posted last: Last night I logged into the
Linksys and disabled outbound traffic from the server. I put a 24/7
block on the server's internet NIC. This morning at 7:50 the Netgear
was unresponsive to ping from my office.
|
I know you don't have any access to configure the modem part of the
Netgear, but do you have any access to configure the router side?
If not, or if unknown, try these ideas: From the customer's side, use a
web browser to access 192.168.100.1, or 192.168.1.1, 192.168.0.1 or
10.1.10.1 the public IP address assigned to the Netgear, or
www.routerlogin.net. If a login/password screen comes up, try cuadmin /
highspeed . I would advise not changing any settings, but rather just
look around. There is probably a "blocked services" (or similar) menu,
and there should be an option for setting a schedule.
If you find that the router has been configured to block services based
on a schedule, any Comcast didn't give you the ability to manage the
router, then call them up, and talk to them again about this situation.
When they've said that the modem doesn't go into sleep mode, they may
not have been thinking about what the router can/can't do, and they may
not have thought about it's ability to block services on a schedule. In
other words, if they were focusing on the modem, they may have
overlooked the anything dealing with the router. On some level they
probably realized it was a combo unit, but they may not have made the
cognitive connection correctly.
If they claim they can't manage the router, ask them to send a tech who
can.
If you are able to look at the router configuration, and you find
there's nothing there that should be a problem, then we've reached a
huge stumbling block. When you shut-down traffic from the server to the
Netgear, that should eliminate the issue of traffic from the LAN
crashing the router. And if Comcast has been honest about the modem logs
indicating that the modem side isn't going down, then we've isolated the
problem to the router side of the Netgear. And since multiple Netgears
have exhibited the same problem, it seems to point towards a
configuration problem on the router side of the Netgear.
BTW... Did you make sure that when they replaced the Netgear they also
replaced the power brick? And have you confirmed that it's not on a
circuit that could be experiencing a surge or brown-out condition during
the time in question? If not, those, and not the configuration, could
still be an issue.
Either way, assuming that Comcast is being truthful about the modem side
not going down, the problem has sufficiently been isolated to the router
side of the Netgear. If they haven't been truthful about the modem
status, then the problem could be further out on their side.
--
Warren H.
==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker |
|
| Back to top |
|
|
$Bill
Guest
|
| Posted: Thu May 10, 2007 6:12 am Post subject: Re: Help needed with intermittent internet |
|
|
JM wrote:
| Quote: |
What exactly should I ask for? I will gladly go back to them. When I've
asked for this type of information before they are not sure what to give me.
|
If it were me, I'd be asking for a separate cable modem without a router.
Then use your Linksys as the router. There's no logical reason why they
can't provision another modem model. If that works, then I'd ask them
for a separate router too if they're supposed to supply one on a bus. acct.
unless of course you don't mind using your own. |
|
| Back to top |
|
|
Fix your Windows Problems - FAST.
FREE Safe Scan Registry Check. Locate & Fix Errors in Minutes!
|
|
$Bill
Guest
|
| Posted: Thu May 10, 2007 6:18 am Post subject: Re: Help needed with intermittent internet |
|
|
Warren H wrote:
| Quote: |
He's using the server as his LAN router. The Netgear router isn't
routing in the lay sense of the word. That is, in the topography of his
network, it's not directing traffic here or there. It is only sitting
there between his server (which is the real router on his LAN), and the
cable modem, but it's opening packets, and repackaging them as a router
does, and not simply passing them through as a bridge would.
|
I didn't get that from the picture he supplied which I inserted below.
The server isn't even mentioned separately and local routing is basically
uneeded and handled by the switch. Either the Linksys or the Netgear
has to be handling the external routing.
Various computers on the LAN (I assume this includes the server)
V
Network switch
V
Linksys
V
Netgear cable modem/router
V
Comcast headend equipment
GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
Like a Motorola or Linksys and tell those idiots to provision it and if
they don't know how, have them ask another ISP or Google and find out. |
|
| Back to top |
|
|
JM
Guest
|
| Posted: Thu May 10, 2007 10:03 pm Post subject: Re: Help needed with intermittent internet |
|
|
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:464272f0$0$9934$4c368faf@roadrunner.com...
| Quote: | Warren H wrote:
He's using the server as his LAN router. The Netgear router isn't routing
in the lay sense of the word. That is, in the topography of his network,
it's not directing traffic here or there. It is only sitting there
between his server (which is the real router on his LAN), and the cable
modem, but it's opening packets, and repackaging them as a router does,
and not simply passing them through as a bridge would.
I didn't get that from the picture he supplied which I inserted below.
The server isn't even mentioned separately and local routing is basically
uneeded and handled by the switch. Either the Linksys or the Netgear
has to be handling the external routing.
|
The Linksys is handling the "external routing," in terms of your question,
although I think there is a little misunderstanding about this function.
The Netgear is the cable mode, for sure, but it also "routes" our static
public IP address to/from the Linksys, which I have configured for static IP
address, NAT, and no DHCP. DHCP is handled by the Novell server.
Some confusion surrounds exactly what functions are provided by the Netgear,
and I believe our problem is mostly one of semantics and how each of us
thinks of "router" vs "modem." The Netgear is indeed a router, at least in
terms of Comcast's system, but it's not playing that role in terms of the
subscriber network. This has caused great problems for me in my
conversations with Comcast, because my basic view is this:
- a "modem" is a device that converts/reconverts a particular type of
carrier signal to a signal that can be used by computers and networking
equipment
- a "router" is a device that specifies where network traffic goes
So, what is the Netgear doing? In my mind it's being a "modem," not a
"router." However, in Comcast's world it's very much a router. Practically
speaking, Comcast doesn't route internet traffic "to" the subscriber device
(router, switch, NIC, etc) to which their equipment is attached. They route
internet traffic "to" their device, which then "passes to" the subscriber
device.
This is how I understand it. Of course, my understanding of all this is
changing almost by the hour, so don't hesitate to shoot that one full of
holes, too.
| Quote: | Various computers on the LAN (I assume this includes the server)
|
Yes.
| Quote: | GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
|
My thoughts and words precisely to at least 2-3 of the Comcast support
people. However, this view reflects a misunderstanding of how Comcast (and
perhaps cable providers in general??) do things. With a business account
using a *static* IP address, there is no such beast as a "plain old modem."
Plain Old Modems are for residential and business accounts with a "dynamic"
IP address.
In the Comcast system, there is no method of assigning a static IP address
to a plain old modem.
And, what's even more frustrating, is that Comcast in my area offers exactly
ONE device for business/static provisioning: The Netgear unit we have.
jm |
|
| Back to top |
|
|
Warren H
Guest
|
| Posted: Thu May 10, 2007 11:06 pm Post subject: Re: Help needed with intermittent internet |
|
|
JM wrote:
| Quote: | - a "modem" is a device that converts/reconverts a particular type of
carrier signal to a signal that can be used by computers and
networking equipment
- a "router" is a device that specifies where network traffic goes
So, what is the Netgear doing? In my mind it's being a "modem," not a
"router."
|
A modem is a bridge. A bridge is normally used to connect two different
kinds of physical networks. In this case, it is a bridge between the HFC
network, and the Ethernet network. It operates at layer two of the OSI
network. It doesn't open the IP packets; it only changes the physical
medium over which they're carried.
A router can direct traffic to multiple devices, like the lay definition
would infer. But it doesn't have to. A router, in terms of completer
networking, is a device that works on layer three of the OSI model. It
opens the IP packets, and inspects them. Based on that inspection, it
can direct traffic to multiple devices, or it could do a number of other
things.
In it's application here, it is primarily used to segregate the
subscriber's network from the Comcast network. TCP/IP traffic using
private IP addresses cannot travel between networks. Neither can
transport or network protocols that aren't TCP/IP. The primary purpose
of using a router at this point is segregation of networks, not
direction of traffic. Forget the common dictionary definition of what a
route is, or that the device happens to be named a router. Just because
it's named a router doesn't mean it's directing traffic between multiple
devices, and just because it isn't directing traffic between multiple
devices doesn't mean it's not a router in networking terms.
| Quote: | However, in Comcast's world it's very much a router. Practically
speaking, Comcast doesn't route internet traffic "to" the subscriber
device (router, switch, NIC, etc) to which their equipment is
attached. They route internet traffic "to" their device, which then
"passes to" the subscriber device.
This is how I understand it. Of course, my understanding of all this
is changing almost by the hour, so don't hesitate to shoot that one
full of holes, too.
|
You're using a layman's concept of what a router is. Remember we're
talking networking here. When I say "router", I'm talking about a device
that works on level 3 of the OSI model, and therefore is partially
opening packets in order to decide what to do with them. I don't care if
there's only one path in and out on each side. That's not relevant in
networking terms.
| Quote: | Various computers on the LAN (I assume this includes the
server)
Yes.
GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
My thoughts and words precisely to at least 2-3 of the Comcast support
people. However, this view reflects a misunderstanding of how Comcast
(and perhaps cable providers in general??) do things. With a business
account using a *static* IP address, there is no such beast as a
"plain old modem." Plain Old Modems are for residential and business
accounts with a "dynamic" IP address.
In the Comcast system, there is no method of assigning a static IP
address to a plain old modem.
|
It's mostly a business decision to use a combo device. They *can* assign
a static IP address to a customer's equipment with just a modem. The
modem's IP address, a 10.x.x.x address, is only used to manage the
modem, and is not involved in how traffic gets to or through it. Before
DOCSIS, IP wasn't even used to manage the modem, so modems didn't even
have IP addresses. (The exception was the LanCity system, which could
really be thought of as an early version of DOCSIS.)
The apparent reason why they use a combo device for business customers
is that business customers often have more complex networks than home
users, and the router ensures that the two networks are segregated --
and are segregated by a device that the customer can't accidentally take
out of the picture. Essentially, they're afraid that the customer's
complex, mission critical network is going to be operated by someone who
doesn't understand the OSI model, and why it's essential to have a level
3 device segregating the networks.
| Quote: | And, what's even more frustrating, is that Comcast in my area offers
exactly ONE device for business/static provisioning: The Netgear unit
we have.
|
Then they need to get people who know how to manage it.
When you asked them about a "sleep mode", and they said that there was
no such thing, they were overlooking the ability of the router to block
IP services based on a schedule. Either they were having a cognitive
disconnect, and didn't realize you were talking about the whole device,
and not just the modem part of the combo, or they really don't know what
control they have over their router.
At this point, my confidence that it's the router, not the modem, is
high. You need to be talking to someone who not only knows the box is a
combo device, but understands the difference between the modem and the
router parts, and what they each do. And I'm starting to get the feeling
(based on what you said earlier) that you're not clear about what a
router is as well. Perhaps you don't normally need to know, but whoever
you talk to at Comcast better know, and in this case you need to know so
you can tell whether they know. In other words, someone needs to
understand that a router really does.
(Hint: "A 'router' is a device that specifies where network traffic
goes," as said earlier.)
--
Warren H.
==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker |
|
| Back to top |
|
|
$Bill
Guest
|
| Posted: Thu May 10, 2007 11:18 pm Post subject: Re: Help needed with intermittent internet |
|
|
JM wrote:
| Quote: |
GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
My thoughts and words precisely to at least 2-3 of the Comcast support
people. However, this view reflects a misunderstanding of how Comcast (and
perhaps cable providers in general??) do things. With a business account
using a *static* IP address, there is no such beast as a "plain old modem."
Plain Old Modems are for residential and business accounts with a "dynamic"
IP address.
In the Comcast system, there is no method of assigning a static IP address
to a plain old modem.
|
You're not assigning the IP to the modem, but to the router connected to the
modem. In your case it's all in one Netgear box. Many people have static
IPs to their networks (1 or more) - they just pay a few $/mo for the static
IP(s) and deal with it at the router.
| Quote: | And, what's even more frustrating, is that Comcast in my area offers exactly
ONE device for business/static provisioning: The Netgear unit we have.
|
There's no reason for this. Many ISPs will let you convert from a dynamic IP
to a static IP for $1/mo. It shouldn't make any difference to them what kind
of modem you're using as long as it's on their list of supported devices (and
most ISPs will support several modems). There's something really inept going
on here IMO. It's just a matter of config'ing your router to the static IP. |
|
| Back to top |
|
|
JM
Guest
|
| Posted: Fri May 11, 2007 10:58 am Post subject: Re: Help needed with intermittent internet |
|
|
"Warren H" <wholzem@hotmail.com> wrote in message
news:u4KdnYvCLvq4wt7bnZ2dnUVZ_tijnZ2d@comcast.com...
| Quote: | JM wrote:
- a "modem" is a device that converts/reconverts a particular type of
carrier signal to a signal that can be used by computers and
networking equipment
- a "router" is a device that specifies where network traffic goes
So, what is the Netgear doing? In my mind it's being a "modem," not a
"router."
A modem is a bridge. A bridge is normally used to connect two different
kinds of physical networks. In this case, it is a bridge between the HFC
network, and the Ethernet network. It operates at layer two of the OSI
network. It doesn't open the IP packets; it only changes the physical
medium over which they're carried.
A router can direct traffic to multiple devices, like the lay definition
would infer. But it doesn't have to. A router, in terms of completer
networking, is a device that works on layer three of the OSI model. It
opens the IP packets, and inspects them. Based on that inspection, it
can direct traffic to multiple devices, or it could do a number of other
things.
In it's application here, it is primarily used to segregate the
subscriber's network from the Comcast network. TCP/IP traffic using
private IP addresses cannot travel between networks. Neither can
transport or network protocols that aren't TCP/IP. The primary purpose
of using a router at this point is segregation of networks, not
direction of traffic. Forget the common dictionary definition of what a
route is, or that the device happens to be named a router. Just because
it's named a router doesn't mean it's directing traffic between multiple
devices, and just because it isn't directing traffic between multiple
devices doesn't mean it's not a router in networking terms.
However, in Comcast's world it's very much a router. Practically
speaking, Comcast doesn't route internet traffic "to" the subscriber
device (router, switch, NIC, etc) to which their equipment is
attached. They route internet traffic "to" their device, which then
"passes to" the subscriber device.
This is how I understand it. Of course, my understanding of all this
is changing almost by the hour, so don't hesitate to shoot that one
full of holes, too.
You're using a layman's concept of what a router is. Remember we're
talking networking here. When I say "router", I'm talking about a device
that works on level 3 of the OSI model, and therefore is partially
opening packets in order to decide what to do with them. I don't care if
there's only one path in and out on each side. That's not relevant in
networking terms.
Various computers on the LAN (I assume this includes the
server)
Yes.
GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
My thoughts and words precisely to at least 2-3 of the Comcast support
people. However, this view reflects a misunderstanding of how Comcast
(and perhaps cable providers in general??) do things. With a business
account using a *static* IP address, there is no such beast as a
"plain old modem." Plain Old Modems are for residential and business
accounts with a "dynamic" IP address.
In the Comcast system, there is no method of assigning a static IP
address to a plain old modem.
It's mostly a business decision to use a combo device. They *can* assign
a static IP address to a customer's equipment with just a modem. The
modem's IP address, a 10.x.x.x address, is only used to manage the
modem, and is not involved in how traffic gets to or through it. Before
DOCSIS, IP wasn't even used to manage the modem, so modems didn't even
have IP addresses. (The exception was the LanCity system, which could
really be thought of as an early version of DOCSIS.)
The apparent reason why they use a combo device for business customers
is that business customers often have more complex networks than home
users, and the router ensures that the two networks are segregated --
and are segregated by a device that the customer can't accidentally take
out of the picture. Essentially, they're afraid that the customer's
complex, mission critical network is going to be operated by someone who
doesn't understand the OSI model, and why it's essential to have a level
3 device segregating the networks.
And, what's even more frustrating, is that Comcast in my area offers
exactly ONE device for business/static provisioning: The Netgear unit
we have.
Then they need to get people who know how to manage it.
When you asked them about a "sleep mode", and they said that there was
no such thing, they were overlooking the ability of the router to block
IP services based on a schedule. Either they were having a cognitive
disconnect, and didn't realize you were talking about the whole device,
and not just the modem part of the combo, or they really don't know what
control they have over their router.
At this point, my confidence that it's the router, not the modem, is
high. You need to be talking to someone who not only knows the box is a
combo device, but understands the difference between the modem and the
router parts, and what they each do. And I'm starting to get the feeling
(based on what you said earlier) that you're not clear about what a
router is as well. Perhaps you don't normally need to know, but whoever
you talk to at Comcast better know, and in this case you need to know so
you can tell whether they know. In other words, someone needs to
understand that a router really does.
(Hint: "A 'router' is a device that specifies where network traffic goes,"
as said earlier.)
|
There's a whole bunch up there that my ego would like to clarify, but it
likely would detract from the target. I do understand what a router does.
I
do understand the OSI model. My attempts to generalize and present the
various miscommunications between myself and a room full of Comcast support
people over the past 4 weeks misrepresented the situation.
That a router operates at layer 3 is a fact. That it does much more than
"route" traffic also is a fact. However, I'm having trouble seeing the
pertinence of this information, in the context of your theory concerning
possible cause. If I'm interpreting your comments correctly, you think the
router might be blocking IP traffic according to a schedule. If that's so,
then would we see the internet "down" specific times of day? Should it be
predictably recurring? Could there be other times of the day when the
internet is intermittent? Finally, would a reset of the Netgear "fix" this
type of problem?
jm |
|
| Back to top |
|
|
Fix your Windows Problems - FAST.
FREE Safe Scan Registry Check. Locate & Fix Errors in Minutes!
|
|
|
|
| |
Watched Topics
Search
Register
Log in to check your private messages
Profile
Log in
Memberlist
Usergroups