24 Shared Registration System (SRS) Performance

Prototypical answer:

gTLDFull Legal NameE-mail suffixDetail
.BBCBritish Broadcasting Corporationbbc.co.ukView

SRS overview

Nominet, the registry service provider, will administer a Shared Registry System (SRS) consisting of an Extensible Provisioning Protocol (EPP) interface to the registry. The interface is compliant with Specification 6 (section 1.2), complying with Request for Comments (RFCs) 5910, 5730, 5731, 5732, 5733 and 5734.

The implementation of EPP for dot BBC is based upon Nominetʹs current EPP service for dot UK and will be deployed on the same architecture as the dot UK domain.

Nominet has run the dot UK EPP for the last 8 years and the service is used by 900 registrars, representing over 6 million domains out of the total of 10 million on the register. The dot UK EPP service easily handles over 2 million transactions per day with an average availability for 2011 of 99.90%.

High Level SRS system description

The network infrastructure for Nominetʹs SRS consists of two firewalls, two EPP application servers, and two middleware servers. All are load balanced. This is shown in figure 24.1 of the attachment Q24_SRS_Figures.pdf. The server specifications are shown in table 24.1 of the attachment Q24_SRS_Tables.pdf.

Nominetʹs EPP architecture for dot BBC has been designed using a three-tier architecture. The two EPP application servers handle connection management and authentication along with confirming that requests are well-formed. The two middleware servers handle all business logic and manipulation of domain names and their associated objects. Finally, the registry data is stored in an Oracle database.

All EPP application and middleware servers are load balanced using a pair of f5 Network Big-IP loadbalancers.

Like Nominetʹs dot UK implementation, the EPP network for dot BBC will be fully reachable over Internet Protocol Version 6 (IPv6).

Interconnectivity with other registry systems

All registry systems connect to one clustered Oracle database, which provides a single point of truth and prevents the occurrence of conflicting registration data updates. The synchronisation scheme for the database is asynchronous replication using Oracle Dataguard.

When a domain is registered by a registrar using EPP, an entry is made in the database representing that domain name. Because the Whois reads directly from this database, the domain immediately becomes visible in the Whois with no delay.

Whenever changes are made to nameservers - when domains are registered or deleted or the nameservers are modified - a row is inserted into a database table that represents a list of updates to be made to the zone file. These updates are then pushed into the DNS using the IXFR protocol.

If a domain name is registered or renewed, then the SRS service programmatically triggers an update to the billing system. A chargeable event representing the registration or renewal is generated which feeds into the monthly invoicing system.

Availability and continuity

All components making up Nominetʹs Registry Services, including the EPP service, are provided on duplicated load balanced servers. A minimum of two virtualised servers will be provisioned on separate server racks and configured to each handle half of the traffic. In the event of a problem with one server, the load balancers will automatically direct traffic to the other server. The servers will be set up so that in the event of the loss of one server, the remaining servers will have enough capacity to handle the traffic.

The EPP architecture is shown in Figure 24.1 of the attachment Q24_SRS_Figures.pdf. Nominet will provision the network in full on both their primary and secondary datacentres. In particular, the database will be replicated in both datacentres. Nominetʹs two datacentres will be connected by two 10GB dual path and geographically diverse links. Each link will have a latency of less than one millisecond. Replication between the two datacentres will be asynchronous but the replicated data will only be a few milliseconds behind that of the live data. Should connectivity to one datacentre fail, the other will automatically assume the role of being the primary datacentre. The two datacentres will be connected to Nominetʹs main office by 1GB links. This allows mechanisms to be put in place to avoid possible ʺsplit brainʺ scenarios where connectivity between the datacentres is lost but both believe the other is lost and assume the primary datacentre role. Each datacentre will have a multi-homed 100MB transit link to the outside world. This connectivity will be handled by six Tier-1 providers in order to ensure availability and redundancy. Nominet will also maintain 100MB links to peering points with Internet Exchanges such as the London Internet Exchange (LINX https:⁄⁄www.linx.net⁄) and the London Access Point (LoNAP http:⁄⁄www.lonap.net⁄) from each datacentre.

This architecture will allow Nominet to have standard operating procedures to enable transition within minutes if necessary and this procedure will be practiced on a monthly basis, with the secondary data centre becoming the primary and vice versa. The relational database in the secondary datacentre will be asynchronously updated from the primary using Oracleʹs Dataguard Maximum Performance architecture.

In the very unlikely scenario that connectivity was lost to both datacentres (such that none of the six Tier-1 providers could connect to either datacentre), Nominet will maintain a third datacentre in Geneva, Switzerland that will be able to provide essential registry services in such a catastrophe.

Nominet already has a comprehensive business continuity management system with a full set of business continuity plans in place and is certified to the British Standard for business continuity, BS25999-2:2007.


Provisioning applications on load balanced virtual machines means that Nominet can easily provision further servers should the load increase. However, Nominetʹs experience with operating the dot UK top level domain with its 10 million domain names, indicates that two application servers will easily meet the performance requirements in Specification 10 to the Registry Agreement.

The EPP service for dot BBC will be deployed on dedicated virtual servers in Nominetʹs datacentre. The servers making up the dot BBC EPP service will have their own dedicated resources as shown in Figure 24.1 of the attachment Q24_SRS_Figures.pdf.

Connectivity is shared with the other registry systems deployed at the datacentre for dot BBC, dot UK and up to five other gTLDs. The total available bandwith is 10 gigabits per second and the available connectivity for each service will be throttled to an appropriate level to both provide sufficient connectivity for the EPP traffic levels and to mitigate against the impact of any traffic surges.


Nominet measures the internal processing time of all commands submitted to the EPP server to ensure that the SLAs given in Specification 10 of the Registry Agreement are met. Recent performance and availability figures for this are given in table 24.2 of the attachment Q24_SRS_Tables.pdf.

Based on all projections Nominet is more than confident that the capacity and redundancy of the SRS system for the dot BBC domain, with an expected 450 domain names after two years, will result in equal performance figures to the dot UK domain.

Resource plan

Nominet has fully developed its SRS systems with pre-launch testing to be done in 2012. Nominet has large development, infrastructure and customer support teams experienced in running all its dot UK services. Nominet will dedicate the following resources and time from these existing teams, as well as additional resources where appropriate, to the pre-launch and post launch maintenance tasks:


- Testbed deployment: 5 days by a system administrator
- Testing: 5 days by a developer
- Packaging: 2 days by a developer
- Production deployment: 5 days by a system administrator

Total pre-launch resource time 17 days.
Post launch

- Customer support: 1 hour per week
- Technical support: 1 hour per week

Total post launch resource 2 hours per week.

Similar gTLD applications: (6)

gTLDFull Legal NameE-mail suffixzDetail
.XFINITYComcast IP Holdings I, LLCfairwindspartners.com-2.42Compare
.COMCASTComcast IP Holdings I, LLCfairwindspartners.com-2.42Compare
.BENTLEYBentley Motors Limiteddemys.com-2.42Compare
.TELECITYTelecityGroup International Limitedhoganlovells.com-2.25Compare
.cymruNominet UKnominet.org.uk-1.97Compare
.walesNominet UKnominet.org.uk-1.76Compare