13

There is no tunneling. This is completely normal. With IP routing you are concerned about the source and destination address which doesn't change unless something is NAT'd. If a router in the middle has an RFC1918 address that's fine as it can still forward transit traffic as again the source and destination is unchanged. Each router will simply reply to ...


10

The distinction you need to draw here is that your ISP is not the internet. Any traffic leaving your ISP to the internet at large or any traffic being received by your ISP from other entities on the internet cannot use these IP addresses. However, your ISP is well within their rights to use these IP addresses however they see fit internally on their own ...


6

I have no practical experience in running CoS/DSCP in ISP networks, but a logical explanation would be that it doesn't make sense to just change fields in a header. Even if I as an intermediate ISP wouldn't be interested in these fields, the receiver or some other intermediate party could be. Resetting DSCP fields just because I'm not using them sounds like ...


6

A few things you should look at: is the bandwidth symmetrical? I.E. do you get 150Mbps download AND 150Mbps upload? is the bandwidth guaranteed? what are the S.L.A. (Service Level Agreement)? In case of SLA breach (that WILL happen), what do you get? What are their support processes? What are the size and reputation of both ISP? In case they are not major ...


6

Is it possible to have an autonomous system with just one IP address? Theoretically, yes, but the ISPs will not advertise any IPv4 prefix larger than /24 or IPv6 prefix larger than /48 on the public Internet. You could certainly have that inside your own network or with another company or ISP, but it will not work on the Internet. Also, the AS concept is ...


5

Hopefully. A tier 1 provider relies entirely on sending data (and routes for incoming data) to customers and peers, they have no upstream providers. That means if you rely on a single tier 1 for transit and they get into a peering dispute you will lose access to parts of the internet. If you are going to single home you have a lower risk going with a large ...


4

The problem of manipulating paths in BGP is that your peer ASes are free to ignore what your AS wants. There are many steps to deciding which routes are preferred in BGP. You can try to influence your peer ASes with MED, but that doesn't mean your peer ASes will pay any attention to MED. Communities are the same. You need the cooperation of your peer ASes to ...


4

A real leased line, could be performed with TDM on a line with for example SDH, TDH or SONET with a CSU/DSU on the customer site (a layer 1 leased line?) This depends - usually a (rare) leased physical line is just copper or (dark) fiber. It's up to you what you do with it. A leased circuit could be done with a ATM CPE on the customer site, typically ...


4

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 over ordinary phone twisted pair. Coax is a type of physical cable used for so-called Cable TV now used for cable internet technology. In either case, there'...


4

Do they no longer have to buy IP transit from tier 1 networks and can peer directly with them? I can't imagine any Tier 1 provider, in their right mind, would peer with Google for no monetary value. Ever. Google (i.e. Youtube) is a source of a large percentage of global internet traffic, 11% back in 2011. The premise behind a peering agreement is that ...


4

The answer to your first question is on the page you mentioned: Google has 70+ Edge POPs in 32 countries, interconnected via Google's backbone network. This is where we interconnect via peering with other network operators who then deliver Google traffic to users. So Edge POPs are locations where Google interconnects with other networks. I'm not sure, ...


4

You don't need to be concerned with how any ISP runs their network. All that matters to you is what they hand-off. ISP A gave you MM/10G-SR; ISP B is giving you SM/10G-LR. You will need new fiber drops and new interface modules. While the existing MM fiber might carry the new signal, passing SM over MM is problematic at the best of times -- and only works ...


4

Yes. In fact an agreement with any tier provider is sufficient. The difference is reliability, bandwidth, and cost.


4

The longest prefix/smallest subnet for IPv4 that can be announced on public BGP is /24 = 256 IP addresses. Note that each announcement likely ends up in the global routing table. Limiting the amount of fragmentation (somewhat) protects that table from exploding. Still, it holds close to 900,000 IPv4 prefixes (out of 16 million theoretically).


3

When I worked for an early IaaS provider, we would provide a separate VLAN and associated /29 for a customer, with a dedicated BVI on the distribution router for their first server instance (or for each stand-alone server instance). If the customer had several instances and wanted local-to-local (many customers did not care; their business model was local-...


3

You have an elegant physical setup, but logically, it’s deficient in a lot of ways. You’re relying on layer 2 for all of your connections, which doesn’t provide any real failover your setup should provide. Luckily, you aren’t wasting any bandwidth with STP because you don’t have any redundant links; VLAN 100 and VLAN 200 only have a single way out, if I’m ...


2

You should check FIB on your switch if you find there two records it means that the switch will load-balance. The command is: display fib x.x.x.x 32 verbose In the output you'll also see whether switch will use mpls switching for this FEC and what LSP will it pick. Fields LspFwdFlag and LspToken indicate this.


2

Welcome to Network Engineering! Yes, you have the basic concept correct. In step 3, ISP_A will determine that the path to the destination address goes through ISP_C, so it will forward the datagram to C. ISPs can connect to each other through common peering points or through private interconnections. It's important to remember that ISP_A doesn't know the ...


1

There are several ways to do this. Logical Systems (LSYS) Logical Systems are a means of segmenting your Junos router into multiple logical systems, which have separate configurations, routing protocols, and interfaces. This is similar to having separate routers that happen to share a physical chassis. The neighboring routers, such as your BRAS, have no ...


1

The best way is to ask the smaller ISP to modify their configuration to accept your AS number.


1

Traceroute does use Reverse DNS lookup or reverse DNS resolution (rDNS). Querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address. The process of reverse resolving of an IP address uses PTR records.


1

From what I can gather, you're looking for another /32 of publicly routable space. If so, you will need to contact your provider or even change providers as many residential providers may not be able to offer extra IP space.


1

Not sure what you're aiming at, but the main point is scalability: you bind your L3 interface to a VLAN. A VLAN is a virtual entity as large as the L2 segment - not even limited to a single switch. Essentially, you can keep adding physical interfaces to it as long as you like.


1

I believe to have grasped this from your problem description: new SP delivers a WAN service which happens to have an internet exit "somewhere upstream". CPE-CE link has to be a publicIPv4 /30, as given from new SP to allow to reach the public Internet (via the SPs new WAN), SP mandates that the CE does SourceNAT/Overload, using the said /30 space. the CE ...


1

The first 6 bytes of an ethernet frame are the destination MAC address, the next 6 bytes are the source MAC address. The next two bytes, 13th and 14th bytes, are the payload length (<= 1500) or the EtherType field (>= 1536). An EtherType of 0x8100 indicates the presence of and 802.1Q tag, and the real EtherType field is moved four bytes over. An untagged ...


1

DIDs are assigned by the telcos which own them. A VoIP provider buys a block of DIDs from the telcos it uses where its VoIP network interfaces with the POTS network. Your cell call travels from the cellular network to the POTS network, where it gets routed to the interface with your VoIP provider. POTS call routing is basically the same as it has been for a ...


Only top voted, non community-wiki answers of a minimum length are eligible