Frequently asked questions regarding our FTTB / FTTH products

We have listed answers to the most requently asked questions towards our FTTH products here.

What is firstboot?

Applicable to DKT CPEs: The device is born without firmware, so an appropriate firmware needs to be provisioned to the device via DHCP using options. The device will in its DHCP Discoverer message indicate a vendor-class-identifier = “DKT_firstboot”, “DKT_BF_firstboot” or “DKT_F2_firstboot”, which the DHCP server should respond to with a specific firmware version to be offered, with the filename option, e.g.

filename “dkt_fw_01_06.img”;

then configuration file, which holds the device configuration parameters, needs to be provisioned with the bootfile-name option, e.g.

option bootfile-name “MyCPE_Config.txt”;

Please note that the CPE will request via DCHP discoverer a set of parameters (options), which all needs to be answered by the DHCP server. In any one of them is not answered, then correct boot process can’t be obtained.

Please refer to the individual product user documentation for details about the DHCP option settings.

Where can I get the latest firmware?

Applicable to DKT CPEs: Please refer to www.dktcomega.com, click under Support -> Firmware

Can I download a specific configuration file based on firmware version?

Applicable to DKT CPEs: Yes, during boot process the CPE will generate a DHCP discoverer holding DHCP option 60 indicating the Vendor_Class_Identifier, which includes the current device firmware version, e.g. DKT_Firmware_v01_06. The DHCP server configuration file can be programmed to react to this option and provision a specific configuration based on this information.

Explaination about DHCP option 60:

A DHCP client sends vendor information in all DHCP packets that it sends to the DHCP server to indicate the vendor or the version of the operating system running on the client. This information is sent in the form of a vendor-class identifier option, as specified in RFC2132 section 9.13.

The DHCP servers implementing this specification use the information contained in this option to determine whether a client implements this specification and whether the options defined in this specification should be sent to it. For semantics on the usage of vendor class identifiers, refer to RFC2132 sections 8.4 and 9.13.

Can I assign a specific IP Address to a CPE with a specific MAC Address?

The following instructions can be inserted in the DHCP server settings, please note that host name, IP and MAC Addresses are examples:

host dkt1 {
next-server 10.3.13.250;
server-name “10.3.13.250”;
hardware ethernet 00:19:9f:00:09:ac;
fixed-address 10.3.111.10;}

Is it possible to manage the device via SNMP?

Applicable to DKT CPEs: Yes, please refer to Support tab -> Firmware on www.dktcomega.com for the latest MIBs. These can be integrated with network management application that supports MIB-II.

It is not possible to TELNET into the device, why is that?

Applicable to DKT CPEs: For security reasons the device will not allow any TELNET sessions per default. In order to overrule this setting, please insert the following instruction into the configuration script, which is provisioned to the device during boot up:

telnetd -l /bin/sh

Please note: this instruction has to be the last instruction in the script file!

Some models support that a user name and password can be specified, please refer to device user guides.

What syntax can be used in the configuration script?

Applicable to DKT CPEs: The script provisioned to the CPE at boot up is an ash shell type. The configuration file is pushed to the device in clear text. If encryption is required, then a “on-the-fly” SSH push is required. Details about SSH capabilities are in the device user documentation

I can’t switch traffic between the device ports, why is that?

Applicable to DKT CPEs: For security reasons the device will not allow any switching between the LAN or WAN ports, per default. This can be overruled with the instruction:

switch –enable-lan

Then the device will be programmed to support simple switching between the ports. Please note that CPU port is not accessible from any of the LANs ports, hence communication with the onboard CPU is only possible from the WAN port side.

Which wavelenghts are used on the fiber WAN connections?

Applicable to DKT CPEs: All CPEs (except legacy 100Mbps) are equipped with a bi-directional 100/1000 BASE-Bx-U type, running 1310 nm Tx and 1490/1550 nm RX – SC/PC type. The link partner, typically an access switch needs to operate the opposite, 100/1000 BASE-Bx-D type.
The CATV Rx module is running 1550 nm Rx – SC/APC type, but supports from 1290 … 1600nm, max input level of 0 dBm.

DHCP collocated with TFTP server?

Applicable to DKT CPEs: The DHCP server and TFTP server doesn’t need to be the same physical server. The DHCP server will serve the CPE with an IP Address, and via the option tftp-server-name “”; e.g.

option tftp-server-name “192.168.1.1”

the pointer to the TFTP server is provided. The CPE will then make a TFTP request for the device firmware (if applicable) and configuration, respectively.

Can CATV module be turned off during operation?

Applicable to DKT CPEs: Yes, please refer to Support tab -> Firmware on www.dktcomega.com for the latest MIBs. These can be integrated with network management application that supports MIB-II. The catvSwitch object in dkt_catv.mib can be programmed to turn the CATV module on/off.

Alternatively a TELNET or reboot of the CPE can be made and a new configuration script holding the following instruction can be provisioned:

switch -c 0 (for legacy devices)

dkt_catv_power 0 (for 79734, 79741, 79742 devices)

Can the CPE be rebooted from remote?

Applicable to DKT CPEs: Yes, please refer to Support tab -> Firmware on www.dktcomega.com for the latest MIBs. These can be integrated with network management application that supports MIB-II. The reboot object in dkt_generic.mib can be programmed to reboot the device.

Alternatively a TELNET session to the device can be made (remember to grant access with the instruction: telnetd -l /bin/sh in the configuration script), and type the reboot command.

Can’t control bandwidth management via IEEE 802.3x (Flow Control)

Applicable to DKT 794xx…796xx CPEs:
Per default flow control is disabled on all ports, so switch engine will ignore any PAUSE frames received, and will not parse these frames. It is possible to enable flow control on each of the ports with the syntax:
switch –enable-port-flowcontrol= :<0|1>

Applicable to DKT 797xx CPEs:
Per default flow control is disabled on all ports, so switch engine will ignore any PAUSE frames received, and will not parse these frames. It is possible to enable flow control on each of the ports using the “conf” settings option for the individual ports, please refer to device user documentation for further details.

IGMP snooping, how to configure blocking out of unknown multicasts

Applicable to DKT 794xx…796xx CPEs: In order to ensure a smooth, quick and continued IPTV experience, it is important to configure the switch behavior correctly. First of all it is important to shut off multicast traffic not designated for the STBs in use. Per default the CPE has an IGMP program running, which will make the approprieate switch filter settings for the multicast group, however the individual ports must be configured to block for the unwanted traffic. The same goes for the CPU port (port 5), so the following syntax should be used:

switch –enable-port-block-unknown-multicast=1:1 # Blocks all Multicast Ethernet frames destinated for LAN port 1 with address not present in CPE Address Translation Unit
switch –enable-port-block-unknown-multicast=2:1 # Blocks all Multicast Ethernet frames destinated for LAN port 2 with address not present in CPE Address Translation Unit
switch –enable-port-block-unknown-multicast=3:1 # Blocks all Multicast Ethernet frames destinated for LAN port 3 with address not present in CPE Address Translation Unit
switch –enable-port-block-unknown-multicast=4:1 # Blocks all Multicast Ethernet frames destinated for LAN port 4 with address not present in CPE Address Translation Unit
switch –enable-port-block-unknown-multicast=5:1 # Blocks all Multicast Ethernet frames destinated for CPU port with address not present in CPE Address Translation Unit

The drawback is that broadcast frames are treated multicast frames by the switch, so e.g. ARP packets could be discarded due to the above. This would cause that management of the CPE (done through port 5 CPU port) could be lost, due to ARP request frames from a management host would be filtered by the CPE switch before they arrive to the CPE CPU, due to the block of multicast frames on port 5. Workaround is to use the Copy of ARP frames to CPU port feature. Adding the following syntax to the configuration will pass all ARP frames to the CPE CPU, hence the blocking filter is bypassed:

switch –set-arp-mirroring=0:1 # Enables ARP mirroring for port 0 (WAN), so all incoming ARPs seen on WAN ports wil be copied to CPU port

The functionality works from firmware revision 02_13 and forward.

How to see forwarding table, MAC addresses present on a port?

For 796xx series CPE:

# Get forwarding table

switch –dump-atu

# alternatively use SNMP, use OID: geATU in dkt_ge.mib

For 797xx series CPE:

# Get forwarding table

conf

l2-table get entry address valid

# alternatively use SNMP from firmware 05_17 and later, use OID: f2FWDTable in dkt_f2.mib

How can I limit number of MAC addresses on a port?

For 797xx series CPE:

# an example how to limit number of MAC addresses on LAN port 1 to 3

conf

l2-table set limit-learning port 0 count 3

I’m unable to set the scheduling on the WAN port of the 797xx series

Applicable to 797xx series CPE:

The WAN port is a special port, and has to be treated a bit different than the LAN ports.

# Configure scheduling of the WAN port

Conf

reg set 0x2D8a4

#The value is a 8-bit field, mapping to queue 0 to queue 7. The every bit definition: 0 means strict; 1 means wfq

# The following is a example

reg set 0x2D8a4 0x5

# means (queue0: wfq), (queue 1: sp), (queue 2: wfq), (queue 3: sp), (queue 4: sp) ,(queue 5: sp) ,(queue 6: sp) ,(queue 7: sp)

How to enable transparency mode on 797xx series?

Applicable to 797xx series:

# Enable transparancy mode, so all traffic that enters will pass by the switch

switch –enable-lan
conf <<EOF
vlan set ingress-filter port 0-4 state disable
vlan set transparent state enable
vlan set egress port 0-4 keep-tag ingress-port 0-4 state enable
l2-table set lookup-miss port 0-4 ip-mcast action flood-in-vlan
l2-table set lookup-miss port 0-4 ip6-mcast action flood-in-vlan

exit
EOF

save_configuration

How can I enable DHCP Option 82, DHCP relay on the 797xx series CPE?

# Enable DHCP relay agent:

# Added option ‘-i’ which makes the DHCP relaying agent only add the option 82 field, leaving the BOOTP header untouched.

# Command line arguments can be passed through /etc/init.d/dhcprelayd

# Ex:

/etc/init.d/dhcprelayd start -i –t1 “From port 1” –t2 “LAN port 2”

How to configure SSH password?

Applicable to 797xx series:

Please consult your local DKT representative for the default username/password.

User guide explains how to change the default SSH user name and password.

How is TR-069 application easily started (quick start)

Applicable to 797xx series:

The connection request URL for the CPE is http://<ip>:7547/creq or https://<ip>:7547/creq

The username and password for the ACS can be configured in the DHCP option 43 ACS URL:

http://<username>:<password>@<ipaddress>/cpe.php