Questions tagged [rfc]

For questions about or involving Request for Comments (RFC), where it is a type of publication from the Internet Engineering Task Force (IETF) and the Internet Society (ISOC), the principal technical development and standardisations for the Internet. For instance, you want to know what a specific RFC means or how you interpret it.

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What RFC standards That describe how network headers work at the bit level [duplicate]

I want to understand more deeply how network headers are constructed at the bit level based on byte ordering, but what standard RFC number explains this?
onxy tzy's user avatar
1 vote
1 answer
221 views

Understanding IPv4 model of operation

I'm new to networking and reading RFC791 about IP protocol specification and got some question regarding the paragraph 2.2 Model of Operation. Here is what is discribed: The internet module prepares a ...
Some Name's user avatar
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83 views

Nonsense RFC 4604 forbids IGMP General Queries in SSM range but IGMP General Queries have no range and are send to 224.0.0.1, the all-systems address?

RFC 4604 Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source-Specific Multicast: 2.2.3. IGMPv1 Queries, IGMPv2 and MLDv1 ...
Horst45324's user avatar
0 votes
1 answer
120 views

RFC 1918 nonsensical sentence

I am doing an intern and now under a training. The instructor suggested us of reading the RFCs involved with the topics covered in class. In RFC 1918, they say "An enterprise that decides to use ...
美日月's user avatar
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0 answers
12 views

How does the client verify its own SYN? [duplicate]

The TCP rfc 9293 says this: A 3WHS is necessary because sequence numbers are not tied to a global clock in the network, and TCP implementations may have different mechanisms for picking the ISNs. The ...
user86942's user avatar
1 vote
2 answers
191 views

Are the IP protocols contained in the Protocol Field in IPv4 header, chronologically assigned by date of creation?

when looking at this list here https://en.wikipedia.org/wiki/List_of_IP_protocol_numbers I see IPv6 was given #41, or 0x29. But there are many protocols after #41. Are these other protocols assigned ...
Ryu S.'s user avatar
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2 votes
1 answer
107 views

Do NAT Gateways Need to be the First Address of the Network?

NAT gateways are often given the first usable address in an address space. Do any protocol specs require this? Or is this just a convention? I skimmed RFC 1918 and RFC 2663 but didn't see anything ...
Brett Holman's user avatar
0 votes
1 answer
112 views

RFC Packet Diagrams Full List of Rules

I'm reading RFC 7798, and I'm having trouble understanding the notation on some packet diagrams, such as figure 5,6 from 4.4.2, and figure 2 from 4.1, so far. To be specific, it is the ' : ' from the ...
carce-bo's user avatar
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1 vote
0 answers
43 views

What does the OSPF RFC mean when it says "The master sends the first Database Description Packet"? [duplicate]

I'm trying to reconcile what I've read about the OSPF Master/Slave process, with what the RFC says, with what I'm seeing on the wire. Everything I've read implies the Master starts the LSA exchange by ...
jester's user avatar
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10 votes
2 answers
3k views

Where are 0 TCP/UDP ports banned?

It is well-known that, on most systems, using 0 for the UDP destination port or for the TCP source or destination ports is disallowed. Is this required by RFCs, or is this just common practice? If it'...
joshlf's user avatar
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1 answer
191 views

Difficulty in understanding the concept of "artificial inflate" and "deflate" in the fast recovery phase of TCP

I was going through the text Computer Networking- A Top-Down Approach by Kurose and Ross, there I found subtleties with the TCP congestion control FSM which is shown below: Mainly I am having ...
Abhishek Ghosh's user avatar
1 vote
2 answers
919 views

Why do we need private IP address range?

When it comes to local networks, you have the freedom to use any IP address you want for your network since it doesn't need to communicate on the internet with other devices. However, the RFC ...
Strategist's user avatar
0 votes
2 answers
317 views

Why cant't IPSec's Transport Mode ESP be used in NAT64 although ESP doesn't sign the new IP header?

In RFC6146 stated: Any protocols that protect IP header are incompatible with NAT64. This implies that end-to-end IPsec verification will fail when the Authentication Header (AH) is used (both ...
maximillian1's user avatar
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1 answer
119 views

RFC 6298 application

I got this? How many Fragments that are going to be sent are: 10800 / 1200 = 9 segments to Host B. And the full time is: (9*1200) / 1600000 = 6.75 ms According to RFC 6298 [1]: (2.2) When the first ...
Jonte YH's user avatar
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0 votes
1 answer
77 views

is DIAMETER-EAP Authentication method mutual or one way?

i'm studying the DIAMETER-EAP authentication method and i would like to know if this method can be considered mutual authentication or "one way" authentication. In my opinion this is one way ...
user69377's user avatar
2 votes
1 answer
113 views

How can MLDv2 work according to the RFCs 3810 and 4606?

When IPv6 Stateless Address Autoconfiguration is happening, an interface/node has to join the all-nodes multicast address and the solicited-node multicast address AFTER forming a "tentative" ...
goulashsoup's user avatar
1 vote
1 answer
480 views

DHCP options field [closed]

I have a problem understanding the description of the Pad-Option field of DHCP in RFC 1533: 3.1. Pad Option The pad option can be used to cause subsequent fields to align on word boundaries. ...
TheProgrammer's user avatar
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1 answer
119 views

Why Internet protocol is divided in rows?

In simple words, why IP packet is divided in rows each one is 32 bit in length? For example this attached image shows the IP packet has 32 bit in the first row then another 32 bit and so on. Is it ...
EmadGKamel's user avatar
2 votes
4 answers
10k views

Why isn't 10.0.0.0/8 used instead of 192.168.0.0/16 for private addresses?

RFC 1918 “Address Allocation for Private Internets” (https://www.rfc-editor.org/rfc/rfc1918) specifies 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 as private addresses suitable for unrestricted ...
lmaooooo's user avatar
  • 147
-1 votes
3 answers
418 views

Can u explain this representation of the IPv6 address 1001::1 64?

::1 is for loopback address. An IPv6 address contains 8 16-bit pieces. What do this representation 1001::1 64 mean (what is the full address with all 8 16-bit pieces)?
kamakshi's user avatar
1 vote
1 answer
148 views

Suggestion for Weights for Weighted Round Robin

I have looked over the book "End-to-End QoS Network Design" by Tim Szigeti et al. and RFC4594. The RFC proposes 14 Service class: I have a switch with simple QoS features. It has 14 egress queues on ...
A.A's user avatar
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3 votes
1 answer
61 views

How to handle IPv6 Extension Header Options with action = 01

RFC 8200 section 4.2 states that if a node does not recognize an option type, that node must do some action depending on the 2 higher order bits of the option type. When the higher order bits are 01, ...
ghanan94's user avatar
1 vote
0 answers
30 views

Missing Byte in RFC Packet Notation

In RFC4728 for Dynamic Source Routing (DSR), the route request option is described like this: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 ...
Jordan Mackie's user avatar
2 votes
1 answer
223 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 ...
Josemi 's user avatar
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13 votes
3 answers
3k 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 ...
kamokoba's user avatar
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0 votes
1 answer
143 views

Abstract service primitive

In SNMP RFC documents, often the concept of abstract service primitive (ASP) is used. What is ASP in fact ? I think it is also used in ISO OSI.
Ilja's user avatar
  • 3
7 votes
1 answer
5k views

Cisco BGP Graceful Restart behavior

In our environment we generally have ASR-1000X-2s everywhere peering via iBGP/eBGP. These routers have no redundant RPs, hence cannot keep forwarding traffic while the router reboots or crashes. As ...
Con7e's user avatar
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1 vote
1 answer
158 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 + ...
Elena Gurevich's user avatar
1 vote
1 answer
124 views

IPv6 source address selection: can the source address have a smaller scope than the destination address?

In RFC 6724 section 5 on "Source Address Selection" rule 2 says to "Prefer appropriate scope": If Scope(SA) < Scope(SB): If Scope(SA) < Scope(D), then prefer SB and ...
StackedCrooked's user avatar
0 votes
1 answer
349 views

GSM - RFC for GSM protocol [closed]

I'm working on OpenBTS source code and I need to know if there's any RFC documentation out there for GSM protocol to study? I googled it, but there's no specific RFC for GSM protocol itself. ...
Brian Salehi's user avatar
5 votes
1 answer
809 views

Is Per Vlan Spanning Tree or RPVST an open standard or can it only be implemented by Cisco?

I know there are some standards that are CISCO proprietary but have become open standards. CISCO has also updated the RFC to reflect this. So, is this also true for PVST? Does Juniper or other ...
Prawn Hongs's user avatar
1 vote
2 answers
1k views

Using a Public AS Number Internally

We have BGP between our network and our customers networks and so far each connection uses private AS numbers (on our end we use a different AS number for each connection) We recently got a public AS ...
jmurphyau's user avatar
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23 votes
1 answer
23k views

What is the practical use of a /31 CIDR or 255.255.255.254?

With a /31 subnet, we are left with zero usable hosts. The /31 subnet only has two hosts - one for network and another for broadcast. I am wondering why would someone ever use this subnet.
Bali Vinayak's user avatar
1 vote
1 answer
757 views

What are the component names of CIDR Prefix Notation?

What are the components of the IETF's CIDR Prefix Notation called? 172.16.0.0/16 contains two parts: 172.16.0.0 /16 In the RFC the entire term 172.16.0.0/16 is defined as the "Prefix Notation&...
Shrout1's user avatar
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1 vote
1 answer
247 views

How do ICMP packets travel in a networks?

Questions: I'd like to know how ICMP packets travel in a network? Are they encapsulated within IP datagram? The RFC 792 doesn't explicitly states the layer of ICMP. Are ICMP messages sent using a ...
Charlie_K's user avatar
5 votes
1 answer
175 views

Class A most significant bits '0' as in RFC1166 or older or '00' as suggested in RFC4632?

I was just reading RFC4632 "2. History and Problem Description" and I don't get the part about Class A with MSB '00'. That would in my understanding mean, there are actually only 64 ...
AdamKalisz's user avatar
2 votes
2 answers
744 views

IPv6 in PPP - should be an Interface Identifier negotiated FOR both ends of a link? Clarification of RFC 5072 needed

I am trying to implement IPv6 in an existing VPN PPP software, but having hard time of understanding some of the RFC 5072 sections meaning. Namely, section 4.1. Assumption 1: PPP interfaces do not ...
Evengard's user avatar
  • 123
6 votes
2 answers
2k views

What MAC address do I use to generate a IPv6 Pseudo-Random Global ID

I am setting up a virtual lab environment in the cloud to experiment with IPv6 networks. Bear with me please, I'm new to networking and my grasp of the whole IPv6 subject is quite shaky. Please ...
snrrn's user avatar
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1 vote
1 answer
1k views

UDP checksum calculation on improperly padded packets

Suppose I'm receiving IPv4 UDP packets whose payload is less than 18 octets, so when they are transmitted over Ethernet they have some trailing padding. Between the packets' source and my receiver ...
Corvus Corax's user avatar
0 votes
1 answer
59 views

What are "Unicast identity tokens"?

I was reading an introduction to IPv6 which talks about the depletion of IPv4 addresses. I came across the following line: As noted in RFC 5735 a number of address blocks are reserved for users ...
Gloomy's user avatar
  • 101
1 vote
3 answers
1k views

Why VPWS service - MPLS has a two ethernet frame headers?

I am trying to understand VPWS services, and going through RFC 4448, Encapsulation Methods for Transport of Ethernet over MPLS Networks. Here is the packet capture: Why there is a need for again ...
Shreyas Joshi Joshi's user avatar
1 vote
3 answers
327 views

VXLAN Protocol introduction

[RFC 7348] about VXLAN in the introduction says: Data centers are often required to host multiple tenants, each with their own isolated network domain. Since it is not economical to realize ...
glc78's user avatar
  • 113
1 vote
1 answer
519 views

Does an EIM-NAT work across both UDP and TCP?

I've read RFC 4787, 5382 and 5128 and I just need a bit of clarification. Assume a NAT has Endpoint Independent Mapping behavior for both UDP and TCP. Although I understand that if a machine would ...
HeyM8's user avatar
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1 vote
1 answer
433 views

What kind of clock is used in tcp timestamps

Most modern computers have atleast 3 to 4 clocks in their motherboards to do different kind of operations. For example in my HP motherboard I got 4 clocks. First One 14.31818Mhz used for CPU and ...
jack's user avatar
  • 13
14 votes
3 answers
2k views

Where can I use the IPv6 documentation prefix

We are currently building a networking course with a practical part where students have to configure a small network in a virtual environment. However, we are not sure what ipv6 prefixes we can use ...
sliebald's user avatar
  • 143
73 votes
5 answers
33k views

Is "IPv10" a joke or a serious RFC draft?

Internet Protocol version 10 (IPv10) Specification The name is funny (IPv4 + IPv6 == IPv10), but the actual proposal looks strange (one more packet format to battle incompatibility between packet ...
Vi.'s user avatar
  • 853
1 vote
2 answers
4k views

UDP Sessions and Ephemeral Port Selection

I would like to ask community to help me finding answers to the following questions: According to RFC 6056 an operating system should pseudo-randomly select ephemeral ports for each transport layer ...
Yury's user avatar
  • 113
1 vote
1 answer
1k views

Where is the maximum packet size for TCP identified as 65,535?

In doing online searches, the value "65,535" is often referenced as the maximum packet size for TCP. Where is this stated? I ask because RFC 793 states, in relation to the "Maximum Segment Size" ...
SoCal's user avatar
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1 vote
1 answer
57 views

In inter-domain routing, what methods can I used to specify the set of the ASes that will be traversed?

In RFC 4655, Page 5, the author wrote, "...the path of an inter-AS TE LSP may be computed using a PCE-based path computation model in some ASes, whereas the set of traversed ASes may be specified by ...
user38407's user avatar
3 votes
2 answers
2k views

How does the ipv4 option "record route" work?

As written in the RFC 791 this option is useful to record the addresses of the routers that an ip datagram goes through. I'm sending an ip datagram with an ICMP echo message, i've set the option type (...
Paradox's user avatar
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