FAQ's
Q: Are you proposing that we purchase and own the site hardware, or is this available on a rental/lease basis?
A: Hermes offers purchase and rental options for equipment.
Q: Will you stock all spares and parts that our exact system uses locally?
A: In some locations we have a complete stock of spares, in others we recommend holding your own spares. We will review and advise on spares holdings prior to contract.
Q: What technology does the satellite signal you propose use? SCPC, TDMA, IPoVSAT, or other?
A: The satellite technology we use depends on the requirements of the network. SCPC (single channel per carrier) is used to provide point-point leased lines where a clocked circuit is required.
We frequently use satellite meshing – also known as Multiple Channels per Carrier (MCPC) to optimise use of satellite bandwidth. Under this system, each site on a network uplinks a single carrier which can be received by multiple sites. The carrier includes packets which are addressed to different sites, effectively creating multiple channels per carrier. This can be used to make networks with a star or mesh topology.
Q: How quickly can you get to site to fix a problem?
A: Most problems can be fixed remotely and do not require site attendance. Where site attendance is required to rectify, we aim to have a Hermes engineer or a service partner available to travel to site from the nearest service centre within 4 hours.
Q: When do I need a VSAT? When can I use microwave or fibre?
A: A VSAT is required where alternative solutions do not exist, are unreliable or cannot be commercially negotiated. Hermes’ approach is always to assess the communication requirement first, and then to identify the most cost-effective method of reliably meeting the need. Often a microwave link to the nearest town or city will be a better solution than a VSAT.
Q: Would you please identify the reasons for a star topology?
A: A star topology is often used to provide links to a number of remote nodes. The benefit of the star topology is that it allows sharing of the outbound space segment from the central node, providing a better service for less cost.
Q: What are the options for linking between my head office and your nearest hub earthstation?
A: Choices for the “backhaul” link include:
- dedicated fibre circuit
- MPLS
- VPN over internet
The choice you make will depend on the traffic to be carried (voice, video or just plain data), the bandwidth, the lead time for installation, the duration of the requirement and the cost. We will work with you to identify the best method.
Q: How much bandwidth do I need for my remote site?
A: This depends on the number of users and the applications used. For sites with 1-4 users simply requiring email, thin client and voice, 64-128Kbps may be enough bandwidth, whilst for some applications 256Kbps is a minimum.
Q: How can I optimise the use of my bandwidth?
A: Hermes will assist you to optimise bandwidth usage by prioritisation: we can prioritise by application or by source or destination data compression: data compression at layer 2 can significantly increase data throughput TCP/IP protocol acceleration over satellite access control: we can assist in the design and management of firewall policies aimed at restricting or preventing internet downloads data management policies: review of backup timings and replication policies.
Q: Does Hermes service include moves, adds, and changes to PBX users and Router configuration?
A: Yes
Q: Are all Hermes links monitored remotely 24/7?
A: we monitor satellite signals using a separate monitoring system so that we can quickly identify problems. We monitor and manage all network devices using an SNMP-based system reported centrally.
Q: What response would we expect for break fix activities and what SLA would we expect with you for availability, signal quality, and support services?
A: Our response on break fix will depend on location, spares holdings and other factors. We can provide a four-hour response in many areas.
Q: Why use Frame Relay?
A: We utilise frame relay to build layer-2 managed networks for our clients, typically where multiple nodes (rig, supply base, HQ) are being linked together by multiple physical technologies (VSAT, Microwave, Fibre). We provide a frame relay access device (FRAD) at each client location to present data and if required voice interfaces, and we use the FRAD to manage the individual links.
Frame relay is also very efficient as a voice protocol as it has low packet overhead.
Q: What voice interfaces can you provide?
A: We can provide interfaces for telephones and faxes (FXS), analogue phone lines or analogue PBX lines (FXO), and/or digital lines (ISDN PRI and BRI). We can also provide SIP gateways and management. Analogue tie-lines (E&M) are available if required.
Whichever interface is provided we will work with you and your PBX provider to ensure that voice calls are fully tested and operational.
Q: How much bandwidth do I need to allocate to voice?
A: We recommend using an 8Kbps voice codec, CELP or ACELP. To this we need to add packet overhead. For voice over frame relay this is typically 2-3Kbps. For VoIP this is typically 10-12Kbps, ie total bandwidth will be around 11Kbps for VoFR and 20Kbps for VoIP.
Bandwidth not in use for voice is dynamically reassigned to lower-priority applications.
Q: How can a single space segment be shared amongst multiple sites?
A: There are two basic approaches we use to share bandwidth among your sites so as to make best use of the total satellite bandwidth.
The first and simplest method is that the carrier signal from a given site includes data packets addressed to multiple other sites. Each of the destination sites receives and demodulates the carrier, then discards packets which are not intended for it. This simply and effectively shares the bandwidth available. This method is ideal for small numbers of remote sites, and allows the creation of star and mesh networks at minimal cost. Each site is assigned an individual frequency, and no central management hub is required.
The second method we use involves central management of numbers of remote sites, so that they take it in turn to transmit separate carrier waves on the same satellite frequency. This method makes very good use of the available bandwidth but requires working with a central hub and carries some overhead costs.
The choice between the two systems depends on number and location of sites, and the type and amount of data to be carried.
Q: Why do you recommend Siemens PBX?
A: Siemens PBXs are reliable, robust and simple to programme. The HiPath PBX series includes all the benefits of a high-end PBX at low cost. We have found that Siemens make few changes in physical hardware over the years, so that upgrading existing PBXs is rarely a problem, and we also like their straightforward approach to marketing. Siemens IP features enable us to manage your PBX remotely, and Siemens VoIP allows simple wireless extension of your central site PBX over wireless or cabled ethernet links around the field.
Q: What can we expect the two way latency via satellite to be from Head office to a rig site?
A: There are two components to latency, satellite and backhaul. Satellite latency will typically be around 560-600ms (this reflects the time it takes the signal to be processed in the transmitting and receiving modems, plus the time it takes to travel around 140,000 Km there and back via the satellite). Backhaul latency depends on the location and the choice of backhaul technology but will typically be between 50 and 100ms. Adding a bit for the routers at each end, your ping time will be in the region of 630-720ms.
Q: "Availability" – how do you measure that?
A: Availability is measured using IP pinging and is determined on a monthly basis.
Q: 24/7 helpline – Do you have a trouble ticketing system with customer access?
A: Yes, we have secure web-based access so you can monitor ticket progress.
Q: Can we start our own tickets?
A: Yes
