User's Manual

27
ASSA ABLOY Hospitality
66 1001 001-7
Appendix D: Boot-up procedure
1. When an encoder comes out of reset, it reads its IP configuration
from a non-volatile memory.
2. If 'Dynamic IP Address' is set to Disable (see chapter 7): the encoder
sets its IP address to the address stored in the config memory. Continue at
step 13 below.
3. If 'Dynamic IP Address' is set to Enable (see chapter 7): the encoder
sends a DHCP Request packet with IP destination address 255.255.255.255,
i.e. IP broadcast, requesting its most recently used IP address.
4. If the network/subnet configuration has not changed, the DHCP server will
most likely send a DHCP ACK packet, allowing the encoder to continue to
use the same IP. The DHCP server may use either IP broadcast or unicast for
this packet; broadcast is however most commonly used. Continue at step 10
below.
5. If the DHCP server is unwilling to let the encoder use the same address as
before, or if the requested IP is out of scope, it sends a DHCP NAK.
6. The encoder resets its IP address to 0.0.0.0 and sends a DHCP Discover packet
with IP destination address 255.255.255.255; IP broadcast.
7. If a DHCP server is available, it sends a DHCP Offer packet. Since the encoder
has no valid IP address, the DHCP server must send to IP destination
255.255.255.255; IP broadcast.
8. The encoder receives the offer and sends a DHCP Request packet, as in step 3
above, but this time requests the IP address offered by the DHCP server.
9. The DHCP server sends a DHCP ACK packet, confirming that the encoder may
start using the new IP address. Unlike the ACK in step 4 above, this ACK
packet must be sent to IP destination address 255.255.255.255 (IP broadcast),
since the encoder has not got any confirmed IP address yet.
10.The encoder performs gratuitous ARP (Address Resolution Protocol) to ensure
that no other host has got the same IP.
11.If IP collision is detected, the encoder sends a DHCP Decline packet which
refuses the assigned IP address and restarts the IP acquirement procedure for
the encoder.
12. New functionality, RFID encoder version 2.0.0 and later: If there is no DHCP
server available on the subnet, the encoder self-assigns an IP address from the
IPv4 Local Link address space (169.254.0.0/16), and sends gratuitous ARP to
ensure that no other host has got the same IP.
13. The encoder reads the most recently used Visionline server IP address and
tries to open a TCP connection to the server.
14. If the TCP connection attempt fails, the encoder will continue to try
connections to the same IP over and over again – unless it detects that the
network/subnet setup has changed, e.g. the encoder may have been moved to
a new location. Then it will send an application specific service discovery
request (announcement broadcast) with IP destination address
255.255.255.255; IP broadcast.
14 b. New functionality, RFID encoder version 2.0.0 and later: Even if the
network/subnet setup is unchanged, but long time (one hour) has elapsed