LTE Quick Reference                                   Go Back To Index    Home : www.sharetechnote.com

 

 

 

 

Protocol Configuration Options

 

Protocol Configuration Options (PCO) is a component of NAS message and this component can be carried by many different messages as follows.

  • PDN Connectivity Request
  • ActivateDefaultEPSBearerContextRequest
  • ActivateDefaultEPSBearerContextAccept

Data Structure of PCO is very flexible (complicated) which may give a lot of difficulties in message decoding process. The structure is as follows.

 

 

There are various Container ID as shown below. The list would get longer and longer as specification evolves.

 

Container ID

Description (Network to MS Direction)

0001H

P-CSCF IPv6 Address Request

0002H

IM CN Subsystem Signaling Flag

0003H

DNS Server IPv6 Address Request

0004H

Policy Control rejection code

0005H

Selected Bearer Control Mode;

0006H

Reserved

0007H

DSMIPv6 Home Agent Address

0008H

DSMIPv6 Home Network Prefix

0009H

DSMIPv6 IPv4 Home Agent Address

000AH

reserved

000BH

reserved

000CH

P-CSCF IPv4 Address

000DH

DNS Server IPv4 Address

000EH

MSISDN Request

C021H

LCP (refer to RFC 3232)

C023H

PAP (refer to RFC 3232)

C223H

CHAP (refer to RFC 3232)

8021H

IPCP (refer to RFC 3232)

FF00H

FFFFH reserved for operator specific use.

 

 

Example 1 : 271B80802110030000108106C0A801028306C0A80102000D04C0A80102

    Octet 1 (Protocol Configuration Option IEI): 27H

    Octet 2 (Length of protocol configuration options contents): 1BH=27

    Octet 3 : 80H = 10000000b

      ext = 1

      spare = 0000

      Configuration Protocol = 000

    Octet 4-253 : 802110030000108106C0A801028306C0A80102000D04C0A80102

      Protocol ID 1 : 8021H (IPCP)

      Length of Protocol ID 1 Contents : 10H=16

      Protocol ID 1 Contents = 030000108106C0A801028306C0A80102H

      Protocol ID 2 : 0004H(DNS)

      Length of Protocol ID 2 Contents : 04H=4

      Protocol ID 2 Contents = C0A80102H

 

How Network Configure PCO ?

 

The simplest answer is "It is completely up to Network !", but one common scenario is "It sends whatever requested by PCO from UE" as shown below.

    i) UE --> NW : PCO in PDN Connectivity Request (UE request the information it want to get)

    ii) UE <-- NW : PCO in Activate Default EPS Bearer Request (NW informs UE of what it want)

 

< Example 1 >

 

In this example, what NW sends in PCO matches exactly what UE requested in PCO

 

Protocol Configuration Options - in PDN Connectivity Request

   Element ID: 0x27

   Length: 26

   [Link direction: MS to network (0)]

   1... .... = Extension: True

   Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

   Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

       Length: 0x10 (16)

       PPP IP Control Protocol

           Code: Configuration Request (1)

           Identifier: 0 (0x00)

           Length: 16

           Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

               Primary DNS Server IP Address: 0.0.0.0

                   Type: Primary DNS Server IP Address (129)

                   Length: 6

                   Primary DNS Address: 0.0.0.0 (0.0.0.0)

               Secondary DNS Server IP Address: 0.0.0.0

                   Type: Secondary DNS Server IP Address (131)

                   Length: 6

                   Secondary DNS Address: 0.0.0.0 (0.0.0.0)

   Protocol or Container ID: DNS Server IPv4 Address Request (0x000d)

       Length: 0x00 (0)

   Protocol or Container ID: IP address allocation via NAS signalling (0x000a)

       Length: 0x00 (0)

 

Protocol Configuration Options - in Activate Default EPS Bearer Request

    Element ID: 0x27

    Length: 27

    [Link direction: Network to MS (1)]

    1... .... = Extension: True

    Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

    Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

        Length: 0x10 (16)

        PPP IP Control Protocol

            Code: Configuration Nak (3)

            Identifier: 0 (0x00)

            Length: 16

            Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

                Primary DNS Server IP Address: 192.168.1.2

                    Type: Primary DNS Server IP Address (129)

                    Length: 6

                    Primary DNS Address: 192.168.1.2 (192.168.1.2)

                Secondary DNS Server IP Address: 192.168.1.2

                    Type: Secondary DNS Server IP Address (131)

                    Length: 6

                    Secondary DNS Address: 192.168.1.2 (192.168.1.2)

    Protocol or Container ID: DNS Server IPv4 Address (0x000d)

        Length: 0x04 (4)

        IPv4: 192.168.1.2

 

 

< Example 2 >

 

In this example, what NW sends in PCO matches roughly what UE requested in PCO, but in detail some of the information (e.g, CSCF IPv6 address) is missing. However, UE may accept this.

 

Protocol Configuration Options - in PDN Connectivity Request

    Element ID: 0x27

    Length: 35

    [Link direction: MS to network (0)]

    1... .... = Extension: True

    Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

    Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

        Length: 0x10 (16)

        PPP IP Control Protocol

            Code: Configuration Request (1)

            Identifier: 0 (0x00)

            Length: 16

            Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

                Primary DNS Server IP Address: 0.0.0.0

                    Type: Primary DNS Server IP Address (129)

                    Length: 6

                    Primary DNS Address: 0.0.0.0 (0.0.0.0)

                Secondary DNS Server IP Address: 0.0.0.0

                    Type: Secondary DNS Server IP Address (131)

                    Length: 6

                    Secondary DNS Address: 0.0.0.0 (0.0.0.0)

    Protocol or Container ID: DNS Server IPv4 Address Request (0x000d)

        Length: 0x00 (0)

    Protocol or Container ID: DNS Server IPv6 Address Request (0x0003)

        Length: 0x00 (0)

    Protocol or Container ID: P-CSCF IPv6 Address Request (0x0001)

        Length: 0x00 (0)

    Protocol or Container ID: P-CSCF IPv4 Address Request (0x000c)

        Length: 0x00 (0)

 

 

Protocol Configuration Options - in Activate Default EPS Bearer Request

    Element ID: 0x27

    Length: 15

    [Link direction: Network to MS (1)]

    1... .... = Extension: True

    Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

    Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

        Length: 0x04 (4)

        PPP IP Control Protocol

            Code: Configuration Nak (3)

            Identifier: 0 (0x00)

            Length: 4

    Protocol or Container ID: P-CSCF IPv4 Address (0x000c)

        Length: 0x04 (4)

        IPv4: 192.168.137.1

 

 

< Example 3 >

 

Protocol Configuration Options - in PDN Connectivity Request

    NAS EPS session management messages: PDN connectivity request (0xd0)

     0001 .... = PDN type: IPv4 (1)

     .... 0001 = Request type: initial request (1)

     ESM information transfer flag

         1101 .... = Element ID: 0xd-

         .... 000. = Spare bit(s): 0x00

         .... ...1 = EIT (ESM information transfer): Security protected ESM information transfer required

     Protocol Configuration Options

         Element ID: 0x27

         Length: 29

         [Link direction: MS to network (0)]

         1... .... = Extension: True

         Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

         Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

             Length: 0x10 (16)

             PPP IP Control Protocol

                 Code: Configuration Request (1)

                 Identifier: 0 (0x00)

                 Length: 16

                 Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

                     Primary DNS Server IP Address: 0.0.0.0

                         Type: Primary DNS Server IP Address (129)

                         Length: 6

                         Primary DNS Address: 0.0.0.0 (0.0.0.0)

                     Secondary DNS Server IP Address: 0.0.0.0

                         Type: Secondary DNS Server IP Address (131)

                         Length: 6

                         Secondary DNS Address: 0.0.0.0 (0.0.0.0)

         Protocol or Container ID: DNS Server IPv4 Address Request (0x000d)

             Length: 0x00 (0)

         Protocol or Container ID: IP address allocation via NAS signalling (0x000a)

             Length: 0x00 (0)

         Protocol or Container ID: IPv4 Link MTU Request (0x0010)

             Length: 0x00 (0)

 

Protocol Configuration Options - in Activate Default EPS Bearer Request

    NAS EPS session management messages: Activate default EPS bearer context request (0xc1)

    EPS quality of service

        Length: 1

        Quality of Service Class Identifier (QCI): QCI 9 (9)

    Access Point Name

        Length: 12

        APN: nxtgenphone

    PDN address

        Length: 5

        0000 0... = Spare bit(s): 0x00

        PDN type: IPv4 (1)

        PDN IPv4: 192.168.1.1 (192.168.1.1)

    Protocol Configuration Options

        Element ID: 0x27

        Length: 27

        [Link direction: Network to MS (1)]

        1... .... = Extension: True

        Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

        Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

            Length: 0x10 (16)

            PPP IP Control Protocol

                Code: Configuration Nak (3)

                Identifier: 0 (0x00)

                Length: 16

                Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

                    Primary DNS Server IP Address: 192.168.1.2

                        Type: Primary DNS Server IP Address (129)

                        Length: 6

                        Primary DNS Address: 192.168.1.2 (192.168.1.2)

                    Secondary DNS Server IP Address: 192.168.1.2

                        Type: Secondary DNS Server IP Address (131)

                        Length: 6

                        Secondary DNS Address: 192.168.1.2 (192.168.1.2)

        Protocol or Container ID: DNS Server IPv4 Address (0x000d)

            Length: 0x04 (4)

            IPv4: 192.168.1.2

 

< Example 4 >

 

Protocol Configuration Options - in PDN Connectivity Request

 

    NAS EPS session management messages: PDN connectivity request (0xd0)

    0011 .... = PDN type: IPv4v6 (3)

    .... 0001 = Request type: initial request (1)

    Access Point Name

        Element ID: 0x28

        Length: 4

        APN: ims

    Protocol Configuration Options

        Element ID: 0x27

        Length: 38

        [Link direction: MS to network (0)]

        1... .... = Extension: True

        Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

        Protocol or Container ID: Internet Protocol Control Protocol (0x8021)

            Length: 0x10 (16)

            PPP IP Control Protocol

                Code: Configuration Request (1)

                Identifier: 0 (0x00)

                Length: 16

                Options: (12 bytes), Primary DNS Server IP Address, Secondary DNS Server IP Address

                    Primary DNS Server IP Address: 0.0.0.0

                        Type: Primary DNS Server IP Address (129)

                        Length: 6

                        Primary DNS Address: 0.0.0.0 (0.0.0.0)

                    Secondary DNS Server IP Address: 0.0.0.0

                        Type: Secondary DNS Server IP Address (131)

                        Length: 6

                        Secondary DNS Address: 0.0.0.0 (0.0.0.0)

        Protocol or Container ID: DNS Server IPv4 Address Request (0x000d)

            Length: 0x00 (0)

        Protocol or Container ID: DNS Server IPv6 Address Request (0x0003)

            Length: 0x00 (0)

        Protocol or Container ID: P-CSCF IPv6 Address Request (0x0001)

            Length: 0x00 (0)

        Protocol or Container ID: P-CSCF IPv4 Address Request (0x000c)

            Length: 0x00 (0)

        Protocol or Container ID: IP address allocation via NAS signalling (0x000a)

            Length: 0x00 (0)

        Protocol or Container ID: IPv4 Link MTU Request (0x0010)

            Length: 0x00 (0)

 

Protocol Configuration Options - in Activate Default EPS Bearer Request

 

    NAS EPS session management messages: Activate default EPS bearer context request (0xc1)

    EPS quality of service

        Length: 1

        Quality of Service Class Identifier (QCI): QCI 5 (5)

    Access Point Name

        Length: 4

        APN: ims

    PDN address

        Length: 9

        0000 0... = Spare bit(s): 0x00

        PDN type: IPv6 (2)

        PDN IPv6 if id: 0000000000000011

    ESM cause

        Element ID: 0x58

        Cause: PDN type IPv6 only allowed (51)

    Protocol Configuration Options

        Element ID: 0x27

        Length: 39

        [Link direction: Network to MS (1)]

        1... .... = Extension: True

        Configuration Protocol: PPP for use with IP PDP type or IP PDN type (0)

        Protocol or Container ID: DNS Server IPv6 Address (0x0003)

            Length: 0x10 (16)

            IPv6: 2001:0:0:1::2

        Protocol or Container ID: P-CSCF IPv6 Address (0x0001)

            Length: 0x10 (16)

            IPv6: 2001:0:0:1::2