Raw Formatting of DHCPv4/v6 Options in ESM

configure port 1/1/5 
    ethernet
            mode access
          encap-type qinq 
    exit
     no shutdown

A capture SAP is used to dynamically detect VLAN ID(s) in incoming DHCP (trigger) packets. This example uses RADIUS authentication along with Python scripting for DHCP message processing and therefore the authentication and Python policies must be configured under the capture SAP.

configure service vpls 10 
    sap 1/1/5:1.* capture-sap create           
        description "circuit-id authentication"           
        trigger-packet dhcp dhcp6            
        dhcp-python-policy "acg"  
        dhcp6-python-policy "acg"            
        authentication-policy "rad"

The MSAP-policy defines the anti-spoofing mode which is set to next-hop MAC (nh-mac) in this example. It also defines the default subscriber management parameters in case that they are not supplied via LUDB or RADIUS.

MSAP-policy configuration is mandatory when a capture-SAP is deployed. In this example, the MSAP-policy name is supplied via RADIUS:

Alc-MSAP-Policy = "msaps"

configure subscriber-mgmt msap-policy ‟msaps”
    sub-sla-mgmt 
        sub-ident-policy ‟sub_ident_pol”
        multi-sub-sap limit 500
    exit
    ies-vprn-only-sap-parameters
        anti-spoof nh-mac 
    exit

In this example the subscriber-interface is a ‛numbered interface’ in which the interface IPv4 address and the interface IPv6 prefixes are explicitly configured. The IPv4 address is used as the default-gateway by the IPoE attached clients. The IPv4 subnet to which this address belongs and the configured IPv6 prefixes are used for routing aggregation and are treated as local subnets/prefixes in the SR OS node routing table.

The managed (dynamic) SAPs are created under the group-interface which contains the reference to the authentication-policy name, the Python script, the v4/6 policy names and the DHCPv4/v6 relay related configuration settings (for example, a reference to DHCP servers). Both the authentication-policy name and the Python policy name referenced under the group-interface must match those configured under the capture-SAP.

configure service vprn 1
    subscriber-interface "int1-1" create
    address 10.10.10.254/24  # Numbered IPv4 subscriber interface. 
    ipv6
        delegated-prefix-len 54 
        subscriber-prefixes
            prefix 2001:db8:3::/48 pd       # Numbered IPv6 subscriber interface.
            prefix 2001:db8:4::/48 wan-host # Numbered IPv6 subscriber interface.
        exit
    exit
    group-interface "g1-1" create
        ipv6
            router-advertisements
                no shutdown
            exit
            dhcp6
                python-policy "acg"  # Python script for DHCPv6 messages. 
                relay
                    server 2001:db8::1001 # IPv6 address of the DHCPv6 server.
                    client-applications dhcp
                    no shutdown
                exit
            exit
        exit
        dhcp
            python-policy "acg”               # Python script for DHCPv4 messages.
            option
                action keep            # Keep option82 in the received DHCP packet.
                vendor-specific-option
                    pool-name # Pool-name obtained via RADIUS (or LUDB) will be passed 
                            # via DHCP relay to the local DHCP server.  This name 
                            # will be used for pool selection in DHCPv4 server.
                exit
            exit
            server 192.168.100.1 # IPv4 address of the DHCPv4 server.
            lease-populate 100   # Maximum number of DHCPv4 lease under each 
                                 # SAP of the group-interface. 
            client-applications dhcp
            no shutdown
        exit
        authentication-policy "rad" # RADIUS authentication policy. 
    exit
exit

The loopback interface is used for the DHCPv4/v6 server binding. It is configured with the IPv4/IPv6 addresses which are referenced from the DHCP relay configuration under the group-interface.

configure service vprn 1
    interface "loopback1-1" create
        address 192.168.100.1/32        # IPv4 address of the DHCPv4 server.
        ipv6
            address 2001:db8::1001/128  # IPv6 address of the DHCPv6 server.
            local-dhcp-server "v6"      # Binding of the DHCPv6 server
                                        # to this interface.
        exit
        local-dhcp-server "v4"          # Binding of the DHCPv4 server 
                                        # to this interface.
        loopback
    exit

The local DHCP server configuration contains the pool selection method, pool information and DHCP options which are passed to the DHCP client at IP address/prefix assignment time.

configure service vprn 1
    dhcp
        local-dhcp-server "v4" 
            use-pool-from-client  # Pool-name received in the DHCP messages 
                                  # sent by the DHCP relay. The pool-name 
                                  # is used in pool selection.
            pool "non-shared-left"
                options
                    dns-server 172.22.250.253  # DHCPv4 option passed on to the client.
                    custom-option 231 string "dhcp server injected custom option 231"
                exit                           # DHCPv4 option passed on to the client.
                subnet 10.10.10.0/24 create
                    address-range 10.10.10.5 10.10.10.100 # IPv4 address range available 
                                                          # for address allocation.
                exit
            exit
        exit
    exit
    dhcp6
        local-dhcp-server "v6" 
            use-pool-from-client
            pool "pd-left" create
                options
                    dns-server 2001:db8:1:1:1:1:1:3
                    custom-option 232 string "v6 custom option 232"
                exit
                prefix 2001:db8:4::/48 pd     # IPv6 prefix range available for delegated 
                                              # prefix allocation by this DHCPv6 server.
                    preferred-lifetime min 20 # Preferred lifetime of the allocated 
                                              # delegated prefix.
                    rebind-timer min 15       # Rebind (T2) time of the allocated 
                                              # delegated prefix.
                    renew-timer min 10        # Renew (T1) time of the allocated 
                                              # delegated prefix.
                    valid-lifetime min 20     # Valid lifetime of the allocated 
                                              # delegated prefix.
                exit
            exit
            pool "wan-left" create
                options
                    dns-server 2001:db8:1:1:1:1:1:3
                    custom-option 232 string "v6 custom option 232"
                exit
                prefix 2001:db8:3::/56 wan-host 
                    preferred-lifetime min 20 # Preferred lifetime of the 
                                              # allocated IPv6 address.
                    rebind-timer min 15       # Rebind (T2) time of the 
                                              # allocated IPv6 address.
                    renew-timer min 10        # Renew (T1) time of the 
                                              # allocated IPv6 address.
                    valid-lifetime min 20     # Valid lifetime of the 
                                              # allocated IPv6 address.
                exit
            exit
            no shutdown
        exit
    exit

The RADIUS authentication-policy is referenced under the capture-sap and under the group-interface configuration.

authentication-policy "rad" create
    password "ALU" hash2
     radius-authentication-server
     router "Base"
         server 1 address 192.168.114.1 secret "ALU" hash2
     exit
     user-name-format circuit-id      
     include-radius-attribute
        circuit-id
        remote-id
        nas-port-id 
        nas-identifier
    exit
exit

The subscriber-identification policy in this example defines a mapping method between the subscriber strings and the predefined subscriber profiles (sub and sla) locally configured on the SR OS node. In our example the subscriber strings (sub and sla) are provided via RADIUS and are directly mapped to the preconfigured sub-profiles and sla-profiles with the matching names.

The subscriber-identification policy can be configured with default subscriber profiles in case the strings are not explicitly obtained via other means (RADIUS, LUSB, Python or statically provisioned). Subscriber-identification policy configuration is mandatory.

sub-ident-policy "sub_ident_pol" create
     sub-profile-map
         use-direct-map-as-default
     exit
     sla-profile-map
         use-direct-map-as-default            
     exit

The following is the configuration of the sub-profile and the sla-profile which are used to setup the subscriber-host. The sla and sub profiles are mandatory when creating subscriber-hosts in SR OS node.

sla-profile "sla-profile-1" create
    ingress
        qos 2 
         exit
    exit
     egress
         qos 2 
         exit
     exit
exit

sub-profile "sub-profile-1" create
exit

The python-policy defined below is applied under the capture-sap and under the group-interface. It references the python-script command which defines the location of the script. A python-policy specifies the DHCP messages along with the direction to which the script processing applies.

The DHCPv4 script in this example is applied to incoming DHCPv4 Request messages. The python script inserts the lease-time option in the DHCPv4 Request message as a hint to the DHCPv4 server.

Similar logic is applied to the incoming Lightweight DHCPv6 Relay Agent

(LDRA) DHCPv6 messages where IA-NA and IA-PD related lease times are altered. Note that in the DHCPv6 case the local DHCPv6 server does not honor the hint and therefore the lease related times are explicitly configured in the DHCPv6 server.

python-script "acg" create
     action-on-fail passthrough #In case of python script failure, do not drop the                                  message but instead continue with message processing                                  in 7750.
     primary-url "ftp://a.b.c.d/pub/configs/alu/SIMS/acg.py"
     no shutdown
exit
python-script "acg6" create  
    action-on-fail passthrough
    primary-url "ftp://a.b.c.d/pub/configs/alu/SIMS/acg6.py"
    no shutdown
exit
python-policy "acg" create  #Python policy that is applied under the capture-sap and
                             under the group-interface.
    dhcp request direction ingress script "acg"
    dhcp6 relay-forward direction ingress script "acg6"
exit

In this example the Python script is located in an external location and downloaded to the SR OS node once the python-script CLI node is enabled (no shutdown).

The DHCPv4 Python script has exception code included (try/except statements). This makes script debugging easier in case one of the commands in the script fails.

For simplicity reasons, the exception code is removed from the DHCPv6 Python script. Note that in real deployments it is recommended for the exception code to be included in all Python scripts.

DHCPv4 Python Script:

from alc import dhcpv4 
try:
    myopt = dhcpv4.getOptionList()
    if myopt != []:
        print "option-list ", repr(myopt)
         print "\n"
except Exception:
    print "Can't retrieve DHCP options"
#lease 500s 8min 20sec
try:
    dhcpv4.set(51,('\x00\x00\x01\xf4', #Insert the lease-time (opt51) in the incoming
                                       DHCPv4 request as a hint to the DHCPv4 server.
except Exception:
    print "Can't set time lease"

DHCPv6 Python Script:

from alc import dhcpv6
import struct
packet = dhcpv6.get_relaymsg()# Extract the original DHCPv6 packet within LDRA.

msgType = ord(packet.msg_type) # Get the message type.
ia_na = packet.get_iana()    # Store the IA-NA option for further processing later on.
ia_pd = packet.get_iapd()    # Store the IA-PD option for further processing later on.


if msgType == 3: # If the message in the LDRA packet is DHCPv6 Request, insert the lease related times in address/prefic options.

    ia_na[0][1] = '\x00\x00\x07\xd0'# Set the renew time (T1) in IA-NA to 2000sec. 
    ia_na[0][2] = '\x00\x00\x0b\xb8'# Set the rebind time (T2) in IA-NA to 3000sec.
    ia_na[0][3][5][0][1] = '\x00\x00\x0f\xa0’  # Set the preferred time in IA-NA to
                                               # 4000sec.
    ia_na[0][3][5][0][2] = '\x00\x00\x0f\xa0'# Set the valid time in IA-NA to 4000sec.
    packet.set_iana(ia_na) # Update the stored packet with the new values for IA-NA.

    ia_pd[0][1] = '\x00\x00\x07\xd0'# Set the renew time (T1) in IA-PD to 2000sec.
    ia_pd[0][2] = '\x00\x00\x0b\xb8'# Set the rebind time (T2) in IA-PD to 3000sec.
    ia_pd[0][3][26][0][0] = '\x00\x00\x0f\xa0’ # Set the preferred time in IA-PD to
                                               # 4000sec.
    ia_pd[0][3][26][0][1] = '\x00\x00\x0f\xa0'# Set the valid time in IA-PD to 4000sec.
    packet.set_iapd(ia_pd) # Update the stored packet with the new values for IA-PD.
    dhcpv6.set_relaymsg(packet) # Insert the packet in the LDRA message. 

Upon authentication, RADIUS returns the Access-Accept message with the following attributes:

Sending Access-Accept of id 66 to 192.168.114.2 port 64384
    Alc-Subsc-Prof-Str = "sub-profile-1"
    Alc-SLA-Prof-Str = "sla-profile-2"
    Alc-MSAP-Interface = "g1-1"
    Alc-MSAP-Policy = "msaps"
    Alc-MSAP-Serv-Id = 1
    Framed-Pool = "non-shared-left"
    Framed-IPv6-Pool = "wan-left"
    Alc-Delegated-IPv6-Pool = "pd-left"
    Alc-ToClient-Dhcp-Options += 0x03040a0a0afe
    Alc-ToClient-Dhcp-Options += 0x0608ac16fafaac16fafb
    Alc-ToClient-Dhcp-Options += 0x0f0b616c636174656c2e636f6d
    Alc-ToClient-Dhcp-Options += 0xe612637573746f6d2074657374206f7074696f6e
    Alc-ToClient-Dhcp-Options += 0x3a040000012c
    Alc-ToClient-Dhcp-Options += 0x3b0400000190
    Alc-ToClient-Dhcp6-Options +=         0x0011001a0000197f00e60012637573746f6d2074657374206f7074696f6e
    Alc-ToClient-Dhcp6-Options +=         0x0017002020010db800010001000100010001000120010db8000100010001000100010002
    Alc-ToClient-Dhcp6-Options +=         0x0018001e0e616c636174656c2d6c7563656e7403636f6d00047465737403636f6d

It is possible to concatenate multiple DHCP options in a single RADIUS Alc-ToClient-DHCP6-Option but for clarity each option is in a separate attribute in this example.

The following table contains the explanation of the DHCP options inserted via RADIUS:

The results are verified via debug output and show commands on the SR OS node, and also via pcap (Wireshark® packet capture) files on the DHCP client side.

Debug output on the SR OS node is enabled for DHCPv4/6 messages and for the Python script.

The DHCP debug output shows the options sent to the client in the DHCPv4/6 Ack/Reply messages.

The following commands enables debugging information to be sent to the current telnet/ssh session:

*A:BNG1# configure  log 
*A:BNG1>config>log# info 
----------------------------------------------
        log-id 50 # Capturing and displaying debug output is configured via log.
            from debug-trace # Capture debug output.
            to session     # Output the debug to the current tcp/ssh session. 
        exit 
----------------------------------------------

The following commands enable DHCP related debugging:

*A:BNG1>config>log# show debug 
debug
    router "1"
        ip
            dhcp
                detail-level high
                mode egr-ingr-and-dropped
            exit
            dhcp6
                mode egr-ingr-and-dropped
                detail-level high
            exit
        exit
        local-dhcp-server "v4"
            detail-level high
            mode egr-ingr-and-dropped
        exit
        local-dhcp-server "v6"
            detail-level high
            mode egr-ingr-and-dropped
        exit
    exit
   

The following output displays the DHCPv4 Request message as it was received by the SR OS node DHCP server.

This message has been modified by the Python script on ingress and the lease-time option [51] has been inserted as a hint to the DHCPv4 server.

Option [82] is partially added by the access-node (relay-agent —> circuit-id and remote-id) and partially by the internal SR OS node DHCP-relay (pool name).

32830 2014/07/24 03:02:46.44 WEST MINOR: DEBUG #2001 vprn1 DHCP server
"DHCP server:  v4 
Rx DHCP Request

   ciaddr: 0.0.0.0           yiaddr: 0.0.0.0
   siaddr: 0.0.0.0           giaddr: 10.10.10.254
   chaddr: 00:00:65:01:03:01    xid: 0x159dd536

   DHCP options:
   [82] Relay agent information: len = 42
      [1] Circuit-id: ds-left
      [2] Remote-id: remote0
      [9] Vendor-Specific info: len = 22
          Enterprise [6527] : len = 17
          [13] dhcpPool: non-shared-left
   [53] Message type: Request
   [54] DHCP server addr: 192.168.100.1
   [50] Requested IP addr: 10.10.10.34
   [51] Lease time: 500
   [255] End

The next output captures the DHCPv4 ACK message (within the SR OS node) that is on its way to the client.

It can be observed that the DHCPv4 server inserted options are listed first:

• Opt[82] is echoed back by SR OS node DHCPv4 server

• Opt[53], [54], [51] and [1] are by default inserted by the local DHCPv4 server and they cannot be disabled. The value for the lease-time [51] is set by the Python script.

• The next two options ([6] and [231]) are the options configured explicitly in the DHCPv4 server (CLI Inserted DHCP Options ).

The remaining options (with the exception of the end [255] option) are provided by RADIUS and they appear in the exact same order as they appear in the RADIUS Alc-ToClient-Dhcp-Options attributes ( RADIUS inserted raw options ).

There are two options [6] since they are inserted by both DHCP and RADIUS server.

Custom options [231] and [230] are decoded in RADIUS inserted raw options and CLI Inserted DHCP Options .

32834 2014/07/24 03:02:46.44 WEST MINOR: DEBUG #2001 vprn1 PIP
"PIP: DHCP
instance 2 (1), interface index 11 (g1-1), 
   transmitted DHCP Boot Reply to Interface g1-1 (1/1/5:1.3) Port 68

   H/W Type: Ethernet(10Mb)  H/W Address Length: 6
   ciaddr: 0.0.0.0           yiaddr: 10.10.10.34
   siaddr: 192.168.100.1     giaddr: 10.10.10.254
   chaddr: 00:00:65:01:03:01    xid: 0x159dd536

   DHCP options:
   [82] Relay agent information: len = 18
      [1] Circuit-id: ds-left
      [2] Remote-id: remote0
   [53] Message type: Ack
   [54] DHCP server addr: 192.168.100.1
   [51] Lease time: 500
   [1] Subnet mask: 255.255.255.0
   [6] Domain name server: 172.22.250.253
   [231] Unknown option: len = 38, value = 64 68 63 70 20 73 65 72 76 65 72
   20 69 6e 6a 65 63 74 65 64 20 63 75 73 74 6f 6d 20 6f 70 74 69 6f 6e 20 32
   33 31
   [3] Router: 10.10.10.254
   [6] Domain name server: length = 8
             172.22.250.250
             172.22.250.251
   [15] Domain name: alcatel.com
   [230] Unknown option: len = 18, value = 63 75 73 74 6f 6d 20 74 65 73 74
   20 6f 70 74 69 6f 6e
   [58] Renew timeout: 300
   [59] Rebind timeout: 400
   [255] End

The Wireshark® output shown on the next page is captured at the client side (N2X Ixia) and it effectively mirrors what is shown in the debug output.

The show command for the DHCP-relay lease state only displays the well known options inserted by the DHCPv4 server. The custom option inserted by the DHCPv4 server and any of the RADIUS supplied options are not kept as part of the DHCP-relay lease state.

*A:BNG1# show service  id 1 dhcp lease-state detail 
===============================================================================
DHCP lease states for service 1
===============================================================================
Service ID           : 1
IP Address           : 10.10.10.34
Client HW Address    : 00:00:65:01:03:01
Subscriber-interface : int1-1
Group-interface      : g1-1
SAP                  : [1/1/5:1.3]
Up Time              : 0d 00:10:46
Remaining Lease Time : 0d 00:07:35
Remaining SessionTime: N/A
Persistence Key      : N/A
 
Sub-Ident            : "ds-left"
Sub-Profile-String   : "sub-profile-1"
SLA-Profile-String   : "sla-profile-2"
App-Profile-String   : ""
Lease ANCP-String    : ""
Lease Int Dest Id    : ""
Category-Map-Name    : ""
 
Lease Info origin    : DHCP
 
Ip-Netmask           : 255.255.255.0
Broadcast-Ip-Addr    : N/A
Default-Router       : N/A
Primary-Dns          : 172.22.250.253
Secondary-Dns        : N/A
Primary-Nbns         : N/A
Secondary-Nbns       : N/A
 
ServerLeaseStart     : 07/24/2014 03:02:46
ServerLastRenew      : 07/24/2014 03:12:46
ServerLeaseEnd       : 07/24/2014 03:21:06
Session-Timeout      : N/A
Lease-Time           : 0d 00:08:20
DHCP Server Addr     : 192.168.100.1
 
Relay Agent Information
  Circuit Id         : ds-left
  Remote Id          : remote0
Radius User-Name     : "ds-left"
-------------------------------------------------------------------------------
Number of lease states : 1
===============================================================================

The DHCPv6 server receives the DHCPv6 Request message with Python modified lease times (preferred, valid, renew and rebind) for IA-NA and IA-PD.

32877 2014/07/24 03:15:28.32 WEST MINOR: DEBUG #2001 vprn1 DHCP server
"DHCP server:  v6 
Rx DHCPv6 RELAY_FORW
     Hop Count : 1
     Link Addr : 2001:db8:4::
     Peer Addr : fe80::200:65ff:fe01:301
     Option : RELAY_MSG (9), Length : 184
       Msg Type : RELAY_FORW (12)
       Hop Count : 0
       Link Addr : ::
       Peer Addr : fe80::200:65ff:fe01:301
       Option : INTERFACE_ID (18), Length : 7
         Interface Id : 64732d6c656674 (ds-left)
       Option : RELAY_MSG (9), Length : 135
         Msg Type : REQUEST (3)
         Trans Id : 0x060000
         Option : ELAPSED_TIME (8), Length : 2
           Time : 0 seconds
         Option : CLIENTID (1), Length : 10
           LL  : HwTyp=0001,LL=000065010301
           00030001000065010301
         Option : SERVERID (2), Length : 10
           LL  : HwTyp=0001,LL=d896ff000000
           00030001d896ff000000
         Option : ORO (6), Length : 4
           Requested Option : IA_NA (3)
           Requested Option : IA_PD (25)
         Option : IA_NA (3), Length : 40
           IAID : 0
           Time1: 2000 seconds
           Time2: 3000 seconds
           Option : IAADDR (5), Length : 24
             Address : 2001:db8:3:1::1
             Preferred Lifetime : 4000 seconds
             Valid Lifetime     : 4000 seconds
         Option : IA_PD (25), Length : 41
           IAID : 0
           Time1: 2000 seconds
           Time2: 3000 seconds
           Option : IAPREFIX (26), Length : 25
             Prefix : 2001:db8:4:400::/54
             Preferred Lifetime : 4000 seconds
             Valid Lifetime     : 4000 seconds
     Option : VENDOR_OPTS (17), Length : 37
       Enterprise : 0000197f
       Option : WAN_POOL (1), Length : 8
         wan-left
       Option : PFX_POOL (2), Length : 7
         pd-left
       Option : PFX_LEN (3), Length : 1

The hinted DHCPv6 lease-times are not honored by the SR OS node DHCPv6 server and instead the SR OS node DHCPv6 server default values are inserted in the outgoing DHCPv6 Reply message towards the client as shown in the output below.

The explicitly configured DHCPv6 options are inserted by the DHCPv6 server first (CLI Inserted DHCP Options ) followed by the RADIUS supplied options inserted by the DHCPv6 relay ( RADIUS inserted raw options ).

There are two DNS options [23] since they are supplied via two sources (DHCPv6 server and RADIUS Alc-ToClient-DHCP-Option VSA).

32885 2014/07/24 03:15:28.32 WEST MINOR: DEBUG #2001 vprn1 TIP
"TIP: DHCP6_PKT
   Outgoing DHCP6 Msg : RELAY_REPLY (13)
   to itf g1-1
     Hop Count : 0
     Link Addr : ::
     Peer Addr : fe80::200:65ff:fe01:301
     Option : RELAY_MSG (9), Length : 265
       Msg Type : REPLY (7)
       Trans Id : 0x060000
       Option : SERVERID (2), Length : 10
         LL  : HwTyp=0001,LL=d896ff000000
         00030001d896ff000000
       Option : CLIENTID (1), Length : 10
         LL  : HwTyp=0001,LL=000065010301
         00030001000065010301
       Option : IA_NA (3), Length : 40
         IAID : 0
         Time1: 600 seconds
         Time2: 900 seconds
         Option : IAADDR (5), Length : 24
           Address : 2001:db8:3:1::1
           Preferred Lifetime : 1200 seconds
           Valid Lifetime     : 1200 seconds
       Option : IA_PD (25), Length : 41
         IAID : 0
         Time1: 600 seconds
         Time2: 900 seconds
         Option : IAPREFIX (26), Length : 25
           Prefix : 2001:db8:4:400::/54
           Preferred Lifetime : 1200 seconds
           Valid Lifetime     : 1200 seconds
       Option : DNS_NAME_SRVR (23), Length : 16
         Server : 2001:db8:1:1:1:1:1:3
       Option : UNKNOWN (232), Length : 20
         763620637573746f6d206f7074696f6e20323332
       Option : VENDOR_OPTS (17), Length : 26
         Enterprise : 0000197f
         Option : UNKNOWN (230), Length : 18
           637573746f6d2074657374206f7074696f6e
       Option : DNS_NAME_SRVR (23), Length : 32
         Server : 2001:db8:1:1:1:1:1:1
         Server : 2001:db8:1:1:1:1:1:2
       Option : DOM_SRCH_LIST (24), Length : 30
         SearchList : .Nokia.com..test.com.
     Option : INTERFACE_ID (18), Length : 7
       Interface Id : 64732d6c656674 (ds-left)

The Wireshark® capture of the DHCPv6 Reply message on the client side mirrors the debug information captured by the SR OS node:

The following command captures the information kept in the SR OS node DHCPv6 relay lease state:

*A:BNG1# show service  id 1 dhcp6 lease-state detail 
===============================================================================
DHCP lease states for service 1
===============================================================================
Service ID           : 1
IP Address           : 2001:db8:3:1::1/128
Client HW Address    : 00:00:65:01:03:01
Subscriber-interface : int1-1
Group-interface      : g1-1
SAP                  : [1/1/5:1.3]
Up Time              : 0d 00:02:41
Remaining Lease Time : 0d 00:17:18
Remaining SessionTime: N/A
Persistence Key      : N/A
 
Sub-Ident            : "ds-left"
Sub-Profile-String   : "sub-profile-1"
SLA-Profile-String   : "sla-profile-2"
App-Profile-String   : ""
Lease ANCP-String    : ""
Lease Int Dest Id    : ""
Category-Map-Name    : ""
Dhcp6 ClientId (DUID): 00030001000065010301
Dhcp6 IAID           : 0
Dhcp6 IAID Type      : non-temporary
Dhcp6 Client Ip      : fe80::200:65ff:fe01:301
Primary-Dns          : N/A
Secondary-Dns        : N/A
Pool Name            : "wan-left"
Dhcp6 Server Addr    : 2001:db8::1001
Dhcp6 ServerId (DUID): 00030001d896ff000000
Dhcp6 InterfaceId    : ds-left
Dhcp6 RemoteId       : N/A
 
Lease Info origin    : DHCP
 
ServerLeaseStart     : 07/24/2014 03:15:28
ServerLastRenew      : 07/24/2014 03:15:28
ServerLeaseEnd       : 07/24/2014 03:35:27
Session-Timeout      : N/A
Radius User-Name     : "ds-left"
-------------------------------------------------------------------------------
Service ID           : 1
IP Address           : 2001:db8:4:400::/54
Client HW Address    : 00:00:65:01:03:01
Subscriber-interface : int1-1
Group-interface      : g1-1
SAP                  : [1/1/5:1.3]
Up Time              : 0d 00:02:41
Remaining Lease Time : 0d 00:17:18
Remaining SessionTime: N/A
Persistence Key      : N/A
 
Sub-Ident            : "ds-left"
Sub-Profile-String   : "sub-profile-1"
SLA-Profile-String   : "sla-profile-2"
App-Profile-String   : ""
Lease ANCP-String    : ""
Lease Int Dest Id    : ""
Category-Map-Name    : ""
Dhcp6 ClientId (DUID): 00030001000065010301
Dhcp6 IAID           : 0
Dhcp6 IAID Type      : prefix
Dhcp6 Client Ip      : fe80::200:65ff:fe01:301
Primary-Dns          : N/A
Secondary-Dns        : N/A
Pool Name            : "pd-left"
Dhcp6 Server Addr    : 2001:db8::1001
Dhcp6 ServerId (DUID): 00030001d896ff000000
Dhcp6 InterfaceId    : ds-left        
Dhcp6 RemoteId       : N/A
 
Lease Info origin    : DHCP
 
ServerLeaseStart     : 07/24/2014 03:15:28
ServerLastRenew      : 07/24/2014 03:15:28
ServerLeaseEnd       : 07/24/2014 03:35:27
Session-Timeout      : N/A
Radius User-Name     : "ds-left"
-------------------------------------------------------------------------------
Number of lease states : 2
===============================================================================