26
votes
Accepted
Is it common for ISPs to connect to each other directly?
Yes, this does happen quite a lot, and it is called private peering. It has some benefits over peering over an IXP:
dedicated bandwidth, you can be sure you can use the full capacity of the ...
- 17.1k
14
votes
Accepted
How do routers on the backbone avoid IP address conflicts?
The RIRs assign addressing to the ISPs. An ISP not following the rules will quickly find itself ostracized and cut off from the rest of the Internet.
IANA owns the addressing and assigns each of the ...
- 98.8k
10
votes
What does "10Gbps wave connection" mean?
Most likely they mean a wavelength on a DWDM path. With DWDM, a fiber operator can use one single pair of fibers to carry a number of different colors (wavelengths) of light using multiplexing. Each ...
- 17.1k
10
votes
What's the difference between autonomous systems, ISPs and RIRs?
You are pretty accurate.
IANA is the Internet Assigned Numbers Authority. Its function is to make sure that numbers that need to be unique are actually unique. That includes protocol values, IPv4 ...
- 6,730
8
votes
Accepted
Why is the internet *not free?
Most ISPs have to buy service from other ISPs to be able to reach every part of the internet. That is called "transit". If you start a small ISP you usually buy transit from one or more bigger ISPs. ...
- 6,730
8
votes
Accepted
Single Public IP Address for multiple physical locations
Based on your edit, it sounds like you want anycast. This is a common among large, global companies. You advertise the same network from multiple places, and routing will take traffic to the closest (...
- 98.8k
8
votes
Is a point-to-point T1 line literally a line in real life?
No. There may be a dedicated circuit between the routers and the nearest telco central office, but between offices they are switched and multiplexed onto other, higher capacity circuits.
Today, most ...
- 67.1k
8
votes
If IPv6 exists, why do we still pay for static IPv4 addresses?
IPv4 and IPv6 are two different protocols. They are not interchangeable without a lot of work.
So if you want to talk to v4 devices you run v4. If you want to talk to v6 devices you run v6. Most of ...
- 67.1k
8
votes
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In practice, how are BGP Advertisement destinations determined and configured?
Some connection between the two ISPs is needed. Dedicated fibers (for example in a datacenter they're both present in) is very common. But there are other possibilities: a layer 2 connection (for ...
- 17.1k
7
votes
Accepted
Prefix hijacked by another ISP
At this moment, there's not that much that ISP's can do to prevent these kind of hijacks except, as you said, doing proper filtering of received and announced prefixes. Unfortunately many ISP's still ...
- 17.1k
7
votes
Accepted
BGP null route when DDoS?
The only answer we can give you is 'talk to your ISP'. Remotely triggered blackholing (RTBH) is an often used technique, but we can't tell if your ISP supports this.
When using RTBH, you can announce ...
- 17.1k
7
votes
What are the significance of different types of routers?
These are not different types of routers, they are different roles. It usually depends on where, topologically, the device placed in the network. Edge routers, for example, are placed at the network ...
- 67.1k
7
votes
Is a point-to-point T1 line literally a line in real life?
Literally? No. Unless the devices were very close, it's very unlikely they would ever have been directly connected. Even 20-30 years ago, in the era of T1's, there were repeaters, digital cross-...
- 31.8k
6
votes
Accepted
Multi-homing and BGP routing with less than /24
Most transit provider will refuse to announce tough BGP a prefix longer than /24. (I.E. /25 for example)
It's related to the size of the routing tables in the routers.
You have to understand that ...
- 19.5k
6
votes
Accepted
Can I set two gateways or more on the same subnet with NAT on a Cisco router?
I think you misunderstood how a router process a packet, thus coming with a solution that is not at all appropriate for your needs.
Why?
Let say computer A has the following configuration:
mac ...
- 19.5k
6
votes
Can ISP know computer MAC address in local network?
A mac address doesn't make it past the first hop (most likely your home router). It stays local to the broadcast network.
IMEI isn't transmitted over wifi, so your ISP will also not see your IMEI. ...
- 246
6
votes
Accepted
How does a ping to a public IP work in my same AS?
In general, traffic to addresses within your network should never go via your upstream ISP. Routers in your network should have a route for the every IP prefix in your network and exchange those via ...
- 17.1k
6
votes
Is it common for ISPs to connect to each other directly?
My understanding is that IXPs provide the primary means of ISPs to connect with each other
I think that is a massive oversimplification.
In general connections between autonomous systems (this ...
- 13.2k
6
votes
Can I make 2 ISP providers' IP addresses into 1 IP address?
While it might not be possible to solve your narrow question about IP addresses without provider-independent addressing and control of your own routing, it is certainly possible to do something the ...
- 16.2k
6
votes
Accepted
What does NAT64 do which can't be done by deploying IPv6 + NAT444?
What it does is simplify your network administration, particularly for large high-traffic networks.
Running dual stack means administering two seperate IP allocations for every network. Running IPv6 ...
- 13.2k
6
votes
Accepted
How can a server from US connect to a tier 1 ISP?
Is there fibers over the ocean ?
They're more under the Ocean but absolutely, you can see a somewhat accurate map of them here. These undersea cables are how continents are interconnected and will ...
- 1,307
5
votes
Accepted
BGP RTBH setup with ISP
Most RTBH implementations at ISPs require you to announce a subnet (let it be a /32) with appropriate BGP community (again, at most ISPs it's 666) to trigger RTBH at PE.
It seems like you're on right ...
- 270
5
votes
Accepted
Could accessed sites over an SSH tunnel be tracked by ISP?
The DNS is issued by default from your local host, not from the proxy, when using SOCKS (probably because SOCKS4 didn't support other way).
Make sure you have checked the checkbox "Remote DNS" in the ...
- 168
5
votes
Accepted
Is DSLAM connected to BRAS through PSTN?
The connectivity between DSLAM and BRAS could be either by ATM or Ethernet and in case the user should be forwarded to another ISP for the authentication and the connectivity L2TP tunnel will be ...
- 1,723
5
votes
Accepted
SONET/T-Carrier differences - MPLS/VPLS bandwidth
Very briefly, SONET/SDH is a high bandwidth optical WAN technology. T-carrier is an electrical (digital) WAN technology.
SONET/SDH is (was) typically used for backbone and inter-provider circuits. ...
- 67.1k
5
votes
Accepted
Why would the local address in case of mobile data network not a private IP address?
Your ISP uses Carrier Grade Nat (CGN) as defined in RFC 6598
As you can see in the RFC the network 100.64.0.0/10 (which encompass your IP 100.127.85.X) is reserved for CGN, so while not a private ...
- 19.5k
5
votes
Layer3 vs Layer2 LACP
The choice between using a L2 or L3 link is really independent of LACP.
Assuming your LACP hashing algorithm choice uses layer 3 information to choose the link (and your ISP does the same), there is ...
- 67.1k
5
votes
Accepted
Internet structure and ISP networks in detail
You're mixing up a couple of things. Also be aware that Internet structures are very different in different countries.
A DSLAM is part of the Digital Subscriber Line technology, delivering Internet ...
- 16.2k
5
votes
Accepted
Can large ISPs really offer 1Gb "dedicated" service to every home and business?
Can large ISPs really offer 1Gb “dedicated” service to every home and
business?
Yes, of course they can, much the same way a business can give every PC user in the company a dedicated 1 Gbps ...
- 98.8k
5
votes
Can I make 2 ISP providers' IP addresses into 1 IP address?
Short answer: No.
When you switch from one ISP to another, your IP address changes. All your chat clients have to detect that and change. A few seconds is actually pretty good.
I would spend my ...
- 67.1k
Only top scored, non community-wiki answers of a minimum length are eligible