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4

Encapsulation requires a protocol. Depending on the protocol, an encapsulating packet is uniquely identified by either EtherType (in layer 2), IP protocol number (in layer 3), transport-layer port number (in layer 4), enabling the gateway to handle the packet as required. The gateway commonly uses additional information from the encapsulating or underlying ...


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I would dare say that you are the victim of the simplistic view presented by network 101 (introduction to networking) courses. Let me start by quoting from ISO 7498 (the OSI reference model). The purpose of this Reference Model of Open Systems Interconnection is to provide a common basis for the coordination of standards development for the purpose of ...


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Models are models - concepts for thought. Like philosophies - sometimes one fits better, some other time the other one. Converting between TCP/IP model and OSI model doesn't make sense. It's like trying to convert a glass that's half full to a glass that's half empty. It's only a matter of perspective. The OSI and TCP/IP models are actually very similar. OSI ...


3

There are a bunch of confusions here. Let's start with the last one. But in OSPF also get to know the routes to it's neighbors after flooding and this neighbor also share routes it's neighbors and so on. It does not(!!!!!). In link state routing neighbors do not share routes of its neighbors, their share topology of their neighbors. Link state routing ...


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General advice, not specific to your router model: Pinging across NAT requires a NAT entry for each Identification value in the ICMP Echo Request header - ICMP doesn't use ports like common transport-layer protocols (UDP, TCP), and that's the only grip a NAT router has on the 'connection' (see RFC 5508 for details). Pinging with a fairly high frequency in ...


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I can't say that this applies to every tunnel imaginable, but this is a general idea how this could work. A tunnel is set up between an entry point and an exit point. In this case the outer packet will have entry point as a source address and exit point as a destination address. The exit point will receive a packet with itself as a destination address. Thus ...


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Why OSPF uses flooding instead of using multicast? Those are two very different concepts. OSPF on a broadcast network uses multicast to exchange routes. It floods by telling ever other OSPF router to which it is connected in the same area about all the routes it knows. We know that flooding is only possible in layer2 switch. That is a completely different ...


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Whenever we talk about OSPF, flooding means "send the data the any router learned form one neighbor to all other adjacent routers. " Actually flooding means a little more then that. Flooding is an algorithm to forward packet through a network which works by having each network node on the path send a packet received from one neighbor to all other ...


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You are running out of I/O memory. This can be tweaked with the memory-size iomem configuration command. You appear to be using ~25%, so 30 or 40 might help. With only 30M free, I wouldn't go too far with that knob. Check what's using IO memory: show memory io allocating-process totals (update) Smart Init is enabled smart init is sizing iomem ID ...


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