HiPath Cordless IP: Synchronisation per Ethernet (regarding IEEE1588)
In difference to the HiPath Cordless IP synchronization over air, the Ethernet based synchronization mechanism (according IEEE1588, PTP Precious Time Protocol) requires fewer configurations. On the other hand, great demands are made on the Ethernet characteristics like loss, delay, jitter etc. Therefore special requirements regarding the Ethernet components (especially to the Ethernet switches) have to be considered. If these values (especially jitter) are bad Sync loses are likely. Please remember, if a HiPath Cordless IP base station loses the Sync it will not accept any calls and will try to resync.
Basic requirement to the LAN to use Sync over LAN
The HiPath Cordless IP base station which provides the Sync signal is called Sync Master, the HiPath Cordless IP base stations(s) which gets the Sync signal is called Sync Slave in the following. One Sync Master can provide the Sync signal to many (or even all) Sync Slaves.
A maximum number of three cascaded Ethernet switches are supported between the Sync Master and a Sync Slave. This means max. 3 switches (hops) between Sync Master and each Sync Slave (for instance: DECT IP base station with Sync Master -> (1) floor switch -> (2) building switch -> (3) floor switch -> DECT IP base station with Sync Slave) Only enterprise grade switches are able to support these requirements (tested switches please see below).
The DECT functionality of all DECT IP base station which is configured as Sync Slaves depends on the availability of the Sync Master. If the Sync Master is not functional (e.g. not online because of network problems) the DECT functionality of all Sync Slave BSIP goes down.
Other Configuration hints In general are the IP network requirements also valid in this scenario (VoIP ready network, every DECT IP base station must be in a flat layer two network with the HiPath Cordless IP SW – which is either on one of the DECT IP base stations or one the DECT IP server). The usage of a dedicated DECT VLAN is highly recommended, the CoS value of the DECT VLAN must be assigned to the highest priority in the network switch.
Consideration of LAN Sync in a customer network
1.) the topology requirement of max. three cascade switches between Sync Master and Sync Slaves is a must,
2.1.) if the customer use one of the following switches the usage of LAN Sync is possible the following switches are already tested and could be used:
- every 24-port PoE Layer2 switch from D-Link; e.g. - D-Link DES-1228P, DES-3028P, DGS-1224TP
- every 24-port PoE Layer2 switch from Hewlett Packard (HP ProCurve Series), e.g. - HP ProCurve 2626-PWR
- Switch Enterasys Switch B3G124 (1Gbit)
- Cisco Catalyst 3560
the following switches are already tested and could not be used: - Netgear FS1008
Remark: If the customer use Layer3 switches, the L3 function of the relevant switch ports have to be deactivated.