Skip to main content
Share Your Experience: Take the 2024 Developer Survey

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.

Filter by
Sorted by
Tagged with
0 votes
1 answer
19 views

Missing ICMP identifier equivalent in ARP protocol and desired arping behavior

Running simultaneously more arping on the same interface and the destination IP address all clients get the responses due missing ICMP identifier equivalent. First, am I correct that there is no ICMP ...
pevik's user avatar
  • 137
1 vote
1 answer
47 views

Does PPP do broadcasting? [duplicate]

Let's consider the scenario below: Router 1 <---> Router 2 <---> Router 3 Routers 1 and 3 establish a link with router 2, then will Router 2 broadcast to the interface connected to routers ...
Darevil294's user avatar
1 vote
2 answers
231 views

what is the purpose of GRE in UDP encapsulation if its unidirectional

I was going through this feature of GRE called GRE-in-UDP encapsulation. The RFC says it is unidirectional and the tunnel traffic is not expected to be returned back to the UDP source port values used ...
RootPhoenix's user avatar
3 votes
1 answer
106 views

Address Field In PPP Protocol

What is the actual use of the Address Field on PPP As I know, it is always set to 11111111 and this doesn't seem to have any purpose because we use ppp we dealing with the direct link communication
Darevil294's user avatar
0 votes
1 answer
62 views

On what basis does a router actually install GRE headers and remove them?

I am learning about networks and I have reached the topic of tunnels. At the same time, I have a need to set up a GRE (Generic Routing Encapsulation) tunnel between a remote server (to route addresses ...
Юрий Паршутин's user avatar
0 votes
1 answer
305 views

In HDLC, how to recognize bit stuffing?

In framing for the HDLC protocol, assume the receiver receives the following string of bits: […] 011111010 […] How can it realize whether the sequence “011111010” is real data, or the result of a bit ...
mgiordi's user avatar
  • 101
0 votes
0 answers
30 views

Conflicting opinions for route aggregation [duplicate]

I am a student and I came accross this question: An ABR in OSPF has in its range networks 10.0.8.9/24 to 10.0.21.0/24. how can it summarise the networks? not necessarily in one prefix. What we ve ...
riverwastaken's user avatar
1 vote
1 answer
78 views

Recognizing the next protocol in MPLS header

How can I know what is the next protocol in MPLS header? I do know that MPLS header does not provide any information about the next protocol, But I somehow need to know how to recognize it, as I am ...
user89902's user avatar
3 votes
1 answer
851 views

How PoE interacts LLDP and LLDP-MED?

I need to research 802.3at PoE PSE capable equipment for a project in my company's network, but I have some knowledge gaps regarding PoE operation and its reliance on LLDP. I took a look over 802.3-...
Marcus's user avatar
  • 183
0 votes
1 answer
17 views

How can GMPLS unify signalization plain of all telecommunications network technologies?

In what way can GMPLS do that unification of signalization of network technologies, by hardware, like MPLS switches, or by network protocols? And what is the role of optical networks in GMPLS? Are ...
Vladimir Pejanovic's user avatar
1 vote
1 answer
775 views

The use of a link local IPv6 address

In a networking course that I'm following, there was a mention of several ways of how IPv6 link local addresses can be used, such as Assigning the link local address of a router/L3 switch as the ...
Mitrixsen's user avatar
  • 803
1 vote
1 answer
75 views

Is there a term for application layer protocols that are responsibilities of network engineers?

In studying network engineering, it is usually taught that network engineers are responsible from physical layer up to transport layer, that is, layer 1-4 only. Obviously, HTTP or HTTPS are off-topic ...
Noob_Guy's user avatar
  • 491
3 votes
1 answer
149 views

Valid uses for IPv4 Options [Community-Wiki]

Engineers building firewall rules often block all IPv4 packets with IPv4 Options set in the header. However, there are a few common and valid use-cases for IPv4 Options. This Q&A is intended to ...
Mike Pennington's user avatar
2 votes
1 answer
55 views

Can a BGP speaker records alternative paths to the same destination?

The BGP RFC 4271 reads : In the context of this document, we assume that a BGP speaker advertises to its peers only those routes that it uses itself (in this context, a BGP speaker is said to "...
user19917937's user avatar
0 votes
0 answers
132 views

How does QUIC encrypt packets containing multiple CRYPTO frames?

TCP is slowly being replaced by QUIC and I'm implementing a component that looks at QUIC packets to extract the server name indication from initial packets. The code is working fine, assuming that: (1)...
juhist's user avatar
  • 465
1 vote
1 answer
359 views

How does QUIC provide delivery guarantee?

I'm struggling to grasp how QUIC implements handshakes in contrast with 3 handshakes in TCP. I came across with this picture on Wikipedia. As QUIC uses UDP, I don't understand how the protocol ensures ...
pacman's user avatar
  • 115
0 votes
1 answer
118 views

How router will send ARP resolve packet when it receive ARP request?

How router will send ARP resolve packet when it receive ARP request ?? Router by default enabled with proxy arp configuration?? If then proxy arp is not configured then what will happen if it receives ...
G.Balamurugan's user avatar
3 votes
1 answer
263 views

Does Network Discovery (rfc2461) preclude ARP sniffing?

I'm debugging a system demonstrating intermittent loss of connection. It's loosing entries from the neighborhood cache while there are active connections. Does Neighbor Discovery (rfc2461) require ...
david's user avatar
  • 133
1 vote
1 answer
132 views

Is the EAP-Request/Identity and EAP-Response/Identity transmitted in the clear in a WPA2 entreprise Wi-Fi setup?

Looking at the WPA2 (Entreprise, let's say PEAP-MSCHAPv2) Wi-Fi protocol, I understand that since WPA2 uses Open System Authentication, and that 802.1X authentication takes place before the 4-way ...
user avatar
0 votes
2 answers
305 views

What is the point of Wi-Fi Association?

In the 802.11-2020 standard, you can read, regarding 802.11 Association To deliver an MSDU within an ESS via the DS, the DS needs to know which AP within the ESS to deliver the MSDU, so that the MSDU ...
user avatar
0 votes
2 answers
602 views

Does window size in tcp header include tcp header size?

Let's say a TCP segments has in the field of "window size" = 1400 bytes. Does that mean that we can send 1400 bytes counted in tcp segments = TCP headers + data or it does specify only ...
tonythestark's user avatar
0 votes
1 answer
2k views

Size of an ethernet frame carrying an arp request using ip (no options) & ethernet?

OKay so I found that this frame has size 72 bytes with no explanation and I can't seem to be able to figure out why . Ethernet payload will be : ip header + arp packet Arp packet with ip & ethrnet ...
tonythestark's user avatar
-1 votes
1 answer
39 views

802.11 Protocol on Different Frequency [closed]

Wifi (and the 802.11 protocol) takes place on 2.4Ghz and 5Ghz frequencies. Is it possible to recreate this protocol on a different frequency (say 500Mhz) and create a functional network using a modded ...
matharpre's user avatar
1 vote
0 answers
235 views

Diffie-Hellman with PSK/PKI in the context of IKEv1

It seems I fail to understand few things about DH's functionality in the context of IKEv1. A little bit of context first: During IKE Main Phase, with the 3rd and 4th messages, the peers each exchange ...
Cosmin Ionut Grosu's user avatar
4 votes
2 answers
987 views

Why two routers connected via PPP don't use ARP but Ethernet requires ARP?

I have read from @Ron Maupin's answer of this question that your two routers are connected via PPP (this is not uncommon), ARP will not be used , but if the two routers are connected via ethernet, ...
S. M.'s user avatar
  • 398
1 vote
2 answers
1k views

How is P actually chosen in P-persistent CSMA?

I am struggling to understand how the probability value P is chosen for P-persistent CSMA for any particular station, what's the logic behind this.I have read from Wikipedia . P-persistent This ...
S. M.'s user avatar
  • 398
1 vote
2 answers
2k views

Why does IPsec not support Multicast/Broadcast?

Many sources site GRE as supporting broadcast/multicast and IPsec does not. Both GRE and IPsec are merely tunneling protocols. Therefore there is nothing inherent about tunneling protocols which ...
jester's user avatar
  • 127
1 vote
1 answer
73 views

Does UDP can be exposed to stateful analysis?

From protocol theory we know that TCP is stateful protocol. Different stateful packet filters do filtration based on connection state. I.e. it can distinguish responses and replies. It's obviously for ...
z0lupka's user avatar
  • 207
0 votes
1 answer
61 views

Could one call a network protocol an algorithm too

Is protocol - the term that is used in mainly networking contexts is nothing but an algorithm ? Could we so say like TCP algorithm ?
pensee's user avatar
  • 101
1 vote
1 answer
84 views

Does RIP v1 store next hop in its routing tables?

Does RIP v1 routing protocol store "next hop" field in its routing tables despite not announcing it in the updates? And if yes, how does it do that, simply by storing the address of the node ...
julespuppy02's user avatar
1 vote
1 answer
99 views

How Pruning avoids loops in Protocol Independent Mulitcast (PIM- SM)?

I can not think of a scenario, how pruning avoid loops in PIM-SM when a router joins a SPT. I understood that it avoids duplicate messages, but how it avoids loops? I want a scenario where the router ...
Sourabh Choure's user avatar
1 vote
1 answer
349 views

What happens to the packets in the sender buffer when "eventually a timeout would be reached" for a **delayed ACK** in a AIMD TCP connection?

In a AIMD TCP connection, What happens to the packets in the sender buffer when "eventually a timeout would be reached" for a delayed ACK for a specific packet at the sender side? Suppose ...
AAEM's user avatar
  • 113
1 vote
2 answers
99 views

rules regarding IPV4 fragments and piecing them together

I'm rolling off my own TCP/IP stack for DOS and I have a question on IPV4 packets. Assuming that a client sends multiple IPV4 fragments, I would predict the MF flag would be set for every fragment ...
Mike's user avatar
  • 11
3 votes
1 answer
188 views

Recommended IPv6 prefix size for PPP to a single host?

I am using PPP to create a IPv6 connection to a remote host. What is the recommended IPv6 prefix size for a single host at the other end of the PPP connection? Should it be /128, because there is ...
njh's user avatar
  • 133
0 votes
1 answer
738 views

Retransmission timer: one per segment or one global timer?

TCP uses various mechanisms to detect packet loss and decide when to retransmit segments. In this question, I am asking about the timeout-based retransmission, wherein a TCP retransmits certain ...
Anakhand's user avatar
1 vote
3 answers
866 views

What would happen if TCP flow control is turned off hypothetically? [closed]

I understand that TCP flow control provides a way for the receiver to backpressure the sender. But what if we eliminated this from the protocol. Of course, the receiver would still ACK everything ...
Shuheng Zheng's user avatar
0 votes
0 answers
12 views

Is there any way to send different data packets together over wireline/wireless link? [duplicate]

I would like to know if there is a technology that allow to send many packets (of different data) together and at the same time over communication link (whether in wireline or wireless networks) of ...
Lee's user avatar
  • 63
0 votes
0 answers
48 views

WAN Frames vs. STS-1 and T1 Frames

I am having trouble understanding the need for WAN frames, such as PPP when using the SONET Protocol or T-Carrier System. Since SONET uses STS-1 frames and T-Carrier uses T1 frames, why is there a ...
Train's user avatar
  • 1
1 vote
1 answer
435 views

I have issue with MSS and window size [duplicate]

I made a short example because I have tried understanding the difference between MSS and window size in tcp header when we consider a sender and a receiver. So let's say sender and receiver use the ...
eyesima's user avatar
  • 113
1 vote
1 answer
49 views

Nature of TCP Timeouts

Are timeouts in TCPs inherently part of sequence numbers, or is it an entirely different component of a TCP packet? I understand that timeouts provide some level of reliabilty to a data stream, in ...
CyberCrusader's user avatar
10 votes
5 answers
5k views

Does the destination port change during TCP three-way handshake?

I'm learning networking programming in C and there is a question bothers me a lot, does the destination port change during TCP three-way handshake? Let's say I have a cilent application running on ...
secondimage's user avatar
3 votes
3 answers
1k views

Do these 2 packets belong to the same tcp socket?

Let's say we have two packets A and B. A: Has source-IP S1 , destination-IP D1 , source-port SP1 , destination-port DP1 B: Has source-IP S2 , destination-IP D1 , source-port SP2 , destination-port DP1 ...
kathelk's user avatar
  • 133
0 votes
1 answer
61 views

Does an application implemented using services of layer n necessarily belong to layer n+1 and implement a protocol in layer n+1?

I was wondering what counts a protocol? When an arbitrary (software or hardware) application is implemented on top of the service of layer n in the Internet Protocol stack or the OSI model, does ...
Tim's user avatar
  • 1,555
0 votes
0 answers
14 views

Does the control packets flow into a router/switch through forwarding plane? [duplicate]

I know there are two platforms in any networking device separating the control packets from the traffic, which I call control plane and data plane. My question is, how does the control packets enter ...
Rakesh Nittur's user avatar
3 votes
2 answers
335 views

Networks theory: Layers, Services and Interfaces

I want to learn about computer networks from the bottom up. I don't really understand the nuances of networking layers, with books mentioning that layers provide services to layers above them, but the ...
Suraaj K S's user avatar
1 vote
1 answer
355 views

Does the first TCP FIN packet (active close) goes with just only FIN bit set?

Suppose we have established TCP connection. The active close process assumes the FIN packet been sent to trigger TCP connection closing. But I can't figure out, is this first (active close) FIN packet ...
budoattack's user avatar
1 vote
1 answer
345 views

Is there any other network protocol than tcp/udp that works with ports?

Do you know at least one protocol (any OSI layer) that, like tcp and udp, works with ports ? Thank you
beauthi's user avatar
  • 13
0 votes
1 answer
203 views

Question about the rebooting state of the DHCP protocol [closed]

Taking into account this diagram... I wonder if a device, after a reboot having a previous known configuration, uses it from the start even tho it's still asking to check if it can continue using ...
Adrián Jaramillo's user avatar
2 votes
2 answers
381 views

Why is delayed segment prevention (TIME_WAIT) in TCP only done for one side?

One of the reasons for TIME_WAIT is to prevent old packets/duplicates, coming in late, to screw up subsequent connections on the same (src ip, src port, dst ip, dst port) quadruplet. That makes sense, ...
Evgeniy Berezovsky's user avatar
1 vote
2 answers
92 views

ICMP distinguish error messages

Can a Internet Control Message Protocol when an error is sent can it tell which datagram that made the error?
Jonte YH's user avatar
  • 147

1
2 3 4 5
10