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Questions tagged [protocol-theory]

For questions about network protocols published in a Standard or RFC. Do not use this tag merely because the question mentions a networking protocol in it. Questions with this tag *could* be closed if they do not explain why the question is relevant and important to answer; this is necessary to avoid issues with tangential / trivial questions or help vampires.

2
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1answer
13 views

EIGRP unequal load balancing, variance command

Is correct to say that the value inserted in the variance command, lets say the value of "2" on a route that has a cost of, lets say "100", will unequally load balance all routes up to a cost of 200 ? ...
2
votes
1answer
15 views

How is SampleRTT measured once every RTT, without measuring every segment?

According to the RFC, SampleRTT is measured once every RTT. My text: Computer Networking: A top-down approach (6ed By: Kurose & Ross) also states, that: Instead of measuring a SampleRTT for ...
2
votes
1answer
67 views

EIGRP Auto-summary

One more question about EIGRP, EIGRP auto-summary what is the impact on the network ? i was reading about but it was not clear for me. And why is it a good Cisco practice to be disabled ? I am ...
1
vote
1answer
25 views

EIGRP metric claculation

I have a question regarding the EIGRP metric system. so if K1 is the Bandwidth and formula is : (K1 * BW + ((K2 * BW) / (256 - LOAD)) + K3 * DELAY ) * (K5 / (RELIABILITY + K4) Whats is BW and ...
0
votes
0answers
16 views

What data structure is the most widely used for routing tables inside routers? [on hold]

Routing tables must be efficient, but how are they implemented internally inside routers. Do they use linked lists, hashmaps, radix trees?
2
votes
2answers
66 views

Why is VPN not a protocol?

Is VPN a layer 3 concept? says "VPN is not a protocol". Is VPN an application instead? Why is VPN not a protocol? How can I tell if something is a protocol or not? Thanks.
2
votes
2answers
52 views

What are the differences between tunneling and regular encapsulation?

What are the difference between tunneling (https://en.wikipedia.org/wiki/Tunneling_protocol) and regular encapsulation (e.g. TCP/UDP over IP, HTTP/SSH over TCP)? Is TCP/UDP over IP considered ...
3
votes
1answer
62 views

Does IEEE 802.11 allow soft-combining?

Out of purely theoretical curiosity, I was wondering whether the IEEE specification for WIFI allows for ARQ with soft-combining. I found a number of publications describing the benefits of soft-...
0
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2answers
27 views

How does a router know it's received an OLSR message?

So I'm working on my own routing protocol based on a alternative to IP, called ILNP, and I'm having trouble understanding how a router differentiates control packets and data packets for OLSR. The IP ...
0
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1answer
25 views

What are the five flag bits in OSPF Hello packet that specify optional capabilities?

What are the five flag bits in OSPF Hello packet that specify optional capabilities? This may be a textbook question and probably less important.
0
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1answer
39 views

“Stop-And-Wait” or “Stop-And-Wait ARQ”?

I was reading about noisy and noiseless channels. Under "noiseless channels", it listed "stop-and-wait", and under "noisy channel", it listed "stop-and-wait ARQ". I was wondering what the difference ...
1
vote
1answer
34 views

IPv4 only host on a dual stack environment

I am looking into migrating to IPv6 at my company. Our plan is to dual-stack everything for now, however, we have a couple of local servers that are IPv4 capable only. The rest of our network will be ...
2
votes
1answer
116 views

What is max speed of WiFi Direct (P2P)?

I'm looking for information on what kind of speeds theoretically can devices connected through WiFI Direct achieve, assuming all devices support WiFi ac?
1
vote
1answer
32 views

Where is the block which caused IPV4 client can not access IPV6 Server

I read many documents which are saying if you are in IPV4 network then you can not access IPV6 network, for example when I was at home I can not access some IPV6 website, such as:ipv6test.google.com. ...
0
votes
1answer
39 views

How to extract transfer rates from a beacon frame (or WLAN_BSS_ENTRY)?

How can I extract the transfer rates (actually I only need the maximum value) from a WLAN_BSS_ENTRY structure (obtained by WlanGetNetworkBssList)? The value wlanRateSet (WLAN_RATE_SET) seems pretty ...
4
votes
1answer
332 views

Will the packet be dropped when the number of hops equals to default TTL?

From my understanding, the default TTL represents the maximum number of hops allowed such that the packet may reach the host. NTP Documentation Archive: ttl - This option is used only with ...
3
votes
1answer
93 views

To what address does ARP reply in the presence of MAC masquerading

The ARP packet has a duplicate of the sender/destination hardware address. Theoretically, you could have a case where a device sent Layer2: From AA:BB:CC:DD:EE:FF To FF:FF:FF:FF:FF:FF Layer3: ARP ...
1
vote
1answer
40 views

How MPTCP closed connection?

how MPTCP connection with more than one subflow closed? what would happen to MPTCP connection if a client decide to close one of the subflows? it would be very kind of you if you explain it step by ...
1
vote
1answer
27 views

Multiaccess link show two Designated Routers in area 0

I have 4 cumulus routers setup with a single ethernet connection from r3 -> r1 -> r2 - r4. From r1, show ip ospf neighbor displays the following: **Neighbor ID Pri State Dead Time ...
2
votes
1answer
40 views

Do the intermediate nodes learn a MAC address in ARP?

my doubt is about the ARP protocol. I know the procedure: if a host wants to know the MAC address of another sends a broadcast frame and the destination answers with its MAC. However, if an ...
1
vote
2answers
89 views

Link Local Address using in NDP (IPv6)

How is using of link local address in NDP. We can discover neighbor by using global address. So why we need link local address in NDP?
11
votes
3answers
2k views

acknowledgment by TCP does not guarantee that the data has been delivered

In RFC 793 there is a part about the acknowledgment of TCP segments: When the TCP transmits a segment containing data, it puts a copy on a retransmission queue and starts a timer; when the ...
0
votes
1answer
55 views

A new version of RIPv2 using different keys for each router

There's a problem in a textbook that is really stumping me. How would you enhance the RIPv2 protocol to provide a (more) secure and scalable schema for distributing the updates? Describe the ...
0
votes
1answer
180 views

TCP errors explain

Could anyone explain these errors: TCP ACKed unseen segment TCP Dup ACK TCP Previous segment not captured TCP Out-Of-Order TCP Retransmission
2
votes
2answers
172 views

NAT Translation Table Port Number

I had a practice question about a NAT-enabled router with outside address 24.34.112.235 and inside network 192.168.1/24 and three inside hosts .1, .2 and .3. The three hosts all open two connections ...
2
votes
2answers
225 views

tcp connection and stream flow question

Could anyone explain the main principe of tcp flow when making a session ? I have take a tcp dump when i'm trying to browse a site. when I analyse the packet by wireshark, i have found many Three way ...
1
vote
1answer
29 views

Is it possible to implement virtual network based on MAC in IP instead of MAC in UDP?

We know that flannel use MAC in UDP to create a overlay network. My question is: UDP header only provides an extra port number fields, let's suppose that one physical machine only run one flanneld ...
4
votes
1answer
239 views

Lost Ethertype in encrypted MACsec frames

MACsec uses an Ethertype of 88E5. This presents an obvious problem when encrypting frames which already have, or should have, another Ethertype. This RedHat blog, for example, states "[MACsec] can ...
3
votes
1answer
38 views

Quagga router advertisement messages are wrong after an address change

I have a problem with Quagga OSPFv3 implementation. I have a Mininet topology with a host connected to a router. I assigned an IPv6 address to the router interface. And I enabled IPv6 ...
1
vote
0answers
45 views

Simulating TCP/IP Illustrated Test Network [closed]

I just recently bought TCP/IP Illustrated volume 1 first edition for cheap and I see that they reference a test network throughout the book that looks like the following Now I'm not the sharpest tool ...
1
vote
1answer
24 views

Question about output of 'lsof -i' and UDP being connectionless

I'v got a simple setup: Server (IP 10.0.0.33) listening on port 7770 using the command: $ netcat -lup 7770 And a client (IP 10.0.0.2) that communicates with the server using: $ nc -u 10.0.0.33 ...
6
votes
2answers
175 views

What Cisco will discard TTL=1 packets for own interface?

There have been a number of questions about router behaviour with IPv4 packets with TTL=1 and apparently contradictory answers. This question is not about what should a host or router do, it is a ...
3
votes
1answer
65 views

Why is retransmission delayed when the RTO is long?

I am new to networking and learning about TCP Timer Management and read this in my textbook: "If the value of time-out (RTO) is too small then unnecessary re-transmission will take place. If time-out ...
3
votes
1answer
38 views

Why are the Address and Control fields constant in PPP protocol?

I saw that address and control fields are constant in PPP protocol. What is the need for even having a field that has constant value in it if we had not have this field then wouldn't it have saved ...
3
votes
2answers
299 views

How does the Transport Layer construct the Pseudo-Header for TCP checksum?

THE TCP Psuedo Header needs sender and destination IP Address and protocol type. All of this informations is present in the network layer/IP header. Since the transport layer cannot access the data ...
3
votes
2answers
42 views

How could a response be sent to the requestor without requestor's address?

I'm reading this talking about the differences between two fire-and-forget message (for example, under UDP) and a request-response communication (for example, under TCP). I came across this: The ...
3
votes
2answers
48 views

Do protocols ever have standards that affect multiple layers of networking?

I'm reading about higher-level protocols such as HTTP and SOAP (concerning the application layer at the highest level) in addition to lower-level ones such as TCP. So far these protocols concern only ...
1
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0answers
46 views

Processing received SACK information in case of reordering

I would like to understand how TCP receiver in established state should treat SACK information of out-of-order and fully within receive window segments, where rcv_nxt < seq_no < rvc_nxt + ...
4
votes
1answer
77 views

Features of ICMP

I'm taking a Network class and learned ICMP, but I cannot understand the reason why below arguments are applied. ICMP message is not generated on header checksum errors If a datagram carrying an ICMP ...
3
votes
1answer
91 views

Packet with wrong source MAC address

When I send a UDP packet with wrong source MAC address but with right source IP address, assuming a reply is sent, will I get the reply because I have right source IP address, or I will not get the ...
1
vote
1answer
308 views

Are Protocols written in programming languages?

The protocols such as HTTP, IP, BGP are written in programming languages or simply plain English text ? If it is written in plain English, then how it is communicated with web browser, switches/...
5
votes
3answers
910 views

Why is a TCP Socket identified by a 4 tuple?

Newbie to networking here. I'm reading the Computer Networking (3rd edition) book, and in section 3.2 they are discussing multiplexing / demultiplexing for both UDP and TCP. In the UDP protocol, a ...
2
votes
1answer
187 views

Is There an Indication in Protocol Stack showing that the End Host is Mobile?

Suppose you are using the Web from your mobile phone. Is there any indication in the internet backbone, when you look at the traffic that shows that the end host is a mobile device? I am sure there ...
1
vote
1answer
80 views

Questions about TCP packets

I am currently in college learning about networks, and I just wanted to make sure that I understood part of the TCP correctly. The question is "What does TCP use to reassemble packets in the correct ...
1
vote
1answer
31 views

Are there any advantage of using multiple threads for a file upload, for an internet connected node? [closed]

I got asked in an intervew recently to design a file upload feature. After initial discussion, The interviewer asked if I can design for multiple threads. My thought was, As the network bandwidth is ...
1
vote
2answers
65 views

How do you know which layer-2 protocol is in action?

We know that the packet contains an IPv4 header, by reading the EtherType field. My question is, how does the NIC know the Layer 2 protocol is Ethernet to begin with? If there are two different Layer ...
1
vote
1answer
84 views

Whether every TCP packet have a Ack Reply?

The TCP Acknowledgements you see in the diagram's green arrows, have ACK numbers separated by 3000(two 1500 bytes). I have a question, why the Ack number is separated by two packets? Or is it just ...
8
votes
2answers
2k views

Where is Ping's “round-trip time” stored in the IP header?

If we use ICMP's ping, we know the TTL and round-trip time are stored in the IP header. In the below IP header map we know TTL's location, but where is the round-trip time? Is it stored in Options?
1
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2answers
57 views

Where is the data fragmented into pieces, and based on what rule?

When data from the application layer pass to transport layer: data may be fragmented into pieces of data, and then the transport layer will be added to the transport layer header (may be TCP header, ...
4
votes
1answer
311 views

Linux TCP stack repeatedly sends “TCP window update” without acknowledging any data

My company is developing its own TCP stack for low-latency purposes and one of the tests involves running 128 instances of ncat on Linux 4.11 to listen to ports 55000 through 55127 and sending data in ...