|
Table of Contents 1. Introduction 3. Dynamic IP Address Allocaion |
1. Introduction
LTE networks are all-IP networks. This means that they deliver all user traffic in IP packets, and provide users with “always-on IP connectivity”. When UE joins an LTE network, a Packet Data Network (PDN) address (i.e. the one that can be used in the PDN) is assigned to the UE for its connection to the PDN, and a default bearer is established in the LTE network (i.e. between UE and P-GW). This default bearer remains connected (i.e. the IP address assigned to the UE during the initial attach remains valid) until the UE is detached from the LTE network.
A default bearer is established for each APN (Access Point Name)1 a user has, and thus a unique IP address is assigned for each APN. An IP address can be an IPv4, IPv6 or IPv4/IPv6 type.
This document will explain how an LTE network allocates an IP address to a user (i.e. UE) when the user initially attaches to the network, by giving an example of a case where UE uses only one PDN, the Internet, and an IPv4 type address is assigned to the UE.
Two different types of IP address allocation will be discussed in this and next documents. This document will cover the basic IP address allocation schemes and procedures, describing how IP addresses are allocated to a user who, while staying in one place, is performing initial attach to the network multiple times (e.g. by turning off UE and then back on). The next document will look into different ways of IP address allocation in case a user performs initial attach from two geographically-separated locations (e.g. City A and City B).
This document is organized as follows:
In Chapter 2, different types of IP address allocation – dynamic and static - and their characteristics will be discussed.
Chapters 3 and 4 will provide the detailed explanation of the dynamic and static IP address allocation procedures, respectively.
|
|
Register | About Us | Sponsor Channel Service (Korean Market) | Advertise | Contact Us | LinkedIn | Our Korean Site
|
|||
|
HQ: 201, Hanho Building 33, Nonhyeon-ro 64-gil, Gangnam-gu, Seoul, 06228, Rep. of KOREA Netmanias USA: 5214 36th Ave. NE Seattle, WA 98105 USA Netmanias was founded in year 2002, and provides in-depth analysis and overview of 4G & 5G mobile, IoT, SDN/NFV, Gigabit Internet and video streaming technologies as well as trends in the evolution of Korean operators’ networks and services Copyright ⓒ 2002-2023 NMC Consulting Group. All rights reserved. |
||||
Hello Team, Thanks for Superb and Detailed Explantion , I am unable to find part 2 of this document , can you provide the link for it.
Thanks
Do we have part-2 please upload it.
I am great fan of this site.
I am sure all the documnet we have now in EPC side.
Can we put something in air interface side.
Following is the over protocal sequence being exchanged between UE and Network. Actually understanding all the details of these steps would be the goal of your whole LTE career.
1) <Cell Search and Detection>
2) MIB
3) SIB 1
4) <Check Cell Selection Criteria>
5) SIB 2 and other SIBs
6) RRC : PRACH Preamble
7) RRC : RACH Response
8) RRC : RRC Connection Request
9) RRC : RRC Connection Setup
>>>>> Can we put something how 1-7 works.
I mean what happens when somebody switchon the mobile.What happens in air interface side.
Like cell search and RACH procedure.
10-14 is coverred in attach procedure.
10) RRC : RRC Connection Setup Complete + NAS : Attach Request + ESM : PDN Connectivity Request
11) RRC : DL Information Transfer + NAS : Authentication Request
12) RRC : UL Information Transfer + NAS : Authentication Response
13) RRC : DL Information Transfer + NAS : Security Mode Command
14) RRC : UL Information Transfer + NAS : Security Mode Complete
I am Kshirod and you can reach me in softkshirod@gmail.com
I have 2 quick questions:
A question on the sequence diagram differences of of fixed and dynamic address allocation:
In dynamic alloc. step 2 points to SGW whereas for static step 2 points to HSS. I do not quite understand if and how the MME distinguishes what to do. Is there just a shortcut in the dynamic sequence diagram? -meaning: the update location request and answers are also part in the complete diagram for dynamic, but these were skipped in the picture?
To Dieter Busch :
When UE send "initial attach request" to MME, UE also includes GUTI (unique id of each MME) information within "initial attach request".
After receiving "IAR" from UE, MME checks GUTI and
- send ULR to HSS if GUTI is different with MME's own
- send CSR to SGW if GUTI is same as MME's own
pls check "Figure 5.3.2.1-1" in TS.23.401 for more explanation
To Netmanias :
Please comment more detailly, example call flow has a potential to make a misunderstanding.
ULR/ULA also can happen in "dynamic IP allocation" scenario. (in this case, HSS does not return any IP address information to MME)
To Dieter Busch,
in ts 23.401, ULR is sent when in following cases:
"If the MME has changed since the last detach, or
if there is no valid subscription context for the UE in the MME, or
if the UE provides an IMSI or
the UE provides an old GUTI which doesn't refer to a valid context in the MME, or
for some network sharing scenario (e.g. GWCN) if the PLMN-ID of the TAI supplied by the eNodeB is different from that of the GUTI in the UE's context, "
To 버너
I do not quit sure all the cases can be concluded into "if GUIT is different with MME' own"?
What if a device executes PSM mode and goes to deep sleep state and wakes up to connect later. What will happen to the IP address? Also, in the case of dynamic IP allocation, is there a possibility that IP address can be changed?
in the following example, user 1 belongs to operator A. When he is on network A, the IP address is allocated by the P-GW of network A.
When he roams on network B, he may still be using the P-GW of network A which can allocate an IP address.
Question: can there be overlap of IP addresses, between a user 2 of Network B who get an IP address by P-GW(B), with user 1 on network B who got an address from P-GW(A)?
@berry blacks:
As far as I know, there can be overlap of IP addresses in that P-GW of network A itself for different APNs in that PGW. What is done to overcome that is VLAN tagging at SGi interface.
As I understand it, the UE gets it's IP address and the DNS IP address if the device is known and reachable.
What happens to the bearer and IP address allocation of the UE when it is powered down or is no longer reachable? Are there timers on network side to re-allocate the used IP address?
Where do i search how many PDN connection does the UE have in wireshark
Dear Netmanias Team,
I had referred to the material LTE IP Address Allocation Schemes I: Basic, it seems only HSS subscription profile is mentioned for statis UE IP allocation, can you please elaborate on the PDN GW Allocation as well during static IP allocation.
Static UE IP can be allocated only if PDN GW is statically assigned to the particular user every time it attaches.
Regards,
Nirav Kapoor
Is the IP address a common IP, can it be seen out of LTE network?
Shouldn't starting address in IP pool be 1.1.0.1 and not 1.1.1.1?
Thanks
Thanks for this comprehensive article ..
i need to know the cases inwhich the UE will be re-assigned with new IP address ?
is it only when attaching to the LTE network , or it can be assigned with new IP address incase of inter rat ?
Is it possible to configure 4 DNS IPs in APN and assign 4 DNS IPs to UE ?
Hello guys,
nice diagram and explanation. I have just additional question. When static alocation for PDN-type IPv4/IPv6 is required, does HSS needs to provide both IPs or IPv6 can be alocated localy on PGW?
Thanks for answer.
in static IP address allocation does it require ULR every time? if user already having its location updated and seating idle and then asks for PDN connection, how IP allocation(static) will happen in this case.
There are multiple IP addresses mentioned in this article to know how to change my ip address on my phone. The first one is a Public IP address is also referred to as an external IP address, which is the address that is designated to your device.
<a href="https://technumus.com/change-my-ip-address-on-my-phone/">change my ip address on my phone</a>It changes every time we tend to establish a new network connection for the device. This is the technique through which your device communicates with networks outside of your own. Secondly, Private IP addresses are the ones that cannot be linked with external networks, although a private IP address is what our devices use to link on private networks.
i wonder whether the assigned ip addrass belong to oprators privite addess space or the address space of PDN ue want to access
When requesting and receiving an IPv4 address, the UE receives only an IP address without subnet mask information. What subnet mask should be used when operating as a 5G router and setting the received IP on the interface?
IPv4 주소를 받는 경우, Subnet mask 정보 없이 IP 주소만 받게 되는데, 5G Router로 동작하여 Interface에 해당 IP를 설정해야 하는 경우에 어떤 Subnet Mask를 사용해야 하나요? 규격에도 Mask에 대한 내용은 못찾겠던데요.
이동통신망에서 subnet mask라는 개념이 필요할까요?