Information Session DNS Service level recommendations and experiences
Information Session DNS Service level recommendations and experiences What is a DNS Service Level (or SLA)? SLAs are a measure of: The ability to resolve names in the name space The ability to obtain authoritative answers for domain delegations
The time taken for changes in registry data to be reflected in the name servers How to measure DNS Service Levels? These service levels are measured in a number of ways. Each has its own metric and recommended level and each deals with vastly different areas that effect DNS availability.
Service Level Measures: Overall Availability Per Name Server Availability Round Trip Time - RTT Packet Loss Average Resolution Time Scheduled Down Time DNS updates Service Level Measures - Overall Availability
This refers to the ability of an authoritative answer for DNS requests. Recommended SLA: 100% Service Level Measures Per Name Server Availability This refers to the availability of an authoritative
answer for a DNS request from each name server individually. Recommended SLA: 99.99% Service Level Measures Round Trip Time & Packet Loss This refers to the ping time and number of packets that go missing in the network that
the name server is connected to. Recommended SLA: 300ms/10% Service Level Measures Average Resolution Times This refers to the average response time for DNS queries from the time the query is received to the time the response is sent.
Recommended SLA: 250ms Service Level Measures Scheduled downtime This refers to the amount of scheduled controlled total DNS downtime allowed. Recommended SLA: No downtime
Service Level Measures DNS updates This refers to the addition, removal and modification of records in the name space, 510min updates are not uncommon, but now days they are average, with providers able to offer instant DNS updates, and propagation using IXFR. Our Recommended SLA: 20mins Max
Recommended Service Levels Summary: 100% Overall DNS Availability 99.99% Per Name Server 300ms RTT (round trip time) 10% Packet Loss maximum 250ms average resolution time No down time 20 mins Max updates How to confirm Service Levels are being met?
Normally the registry operator will perform there own SLA monitoring and report back any variations to the governing body. However you may like to measure these things yourself. Service levels such as: Overall Availability Per Name Server Availability Round Trip Time - RTT
Packet Loss Average Resolution Time DNS updates Can be measured through sampling Taking samples of each measurement over time periods is the easiest and most effective way to ensure service levels are being met. The frequency of these samples is flexible and can be decided between you and your registry
operator. Recommended sampling Frequency: Overall Availability ( 1 min ) Per Name Server Availability ( 1 min ) Round Trip Time RTT ( 1 min ) Packet Loss ( 1 min) Average Resolution Time ( 1 min) DNS updates ( 10 min )
Example: Using mrtg to sample Average Response Time `Daily' Graph (5 Minute Average) Max Response Time: 127.0 ms (0.4%)
Average Response Time: 20.0 ms (0.1%) Current Response
Time: 12.0 ms (0.0%) How to maintain good Service Levels? Choose excellent carry class data centres with redundant network connections, power etc Run multiple secondaries in diverse locations and networks
Maintain a strong and up to date understanding of DNS Use clustering at each location Use quality hardware with different OS Maintain industry best practices, such as those stated in RFC2182, 2870 etc How to co-operate with users to maintain service levels? Target larger commercial ISPs for secondary
services Making use of the existing experienced DNS companies Keep up to date, and provide discussion lists so that you can hear your communities needs. Regularly participate in discussions and show you are taking responsibility for the Name space In summary - key factors to maintaining SLAs
are: Multiple secondaries Network carrier diversity Provider diversity Monitoring Accountability Maintain industry best practice and leverage existing industry experience Thanks for listening
Rethinking the supervisory process Kerstin af Jochnick, Chair of CEBS Madrid 15 June 2009 Outline The role of CEBS The Commission's proposal CEBS's work on convergence Conclusions The role of CEBS - objectives and tasks The role of CEBS -...
Ground Water Erosion and Deposition. When rain falls and snow melts, not all of the water evaporates or becomes runoff. Some water soaks into the ground. There it fills the openings in the soil and tricklets into cracks and spaces...
Overview of Unsteady Flow Modeling With HEC-RAS Gary W. Brunner, P.E. Introduction Overview New Geometric Features for HEC-RAS Geometric pre-processor Boundary and initial conditions Unsteady flow simulation manager Post-processor Additional graphics/tables to view results Overview Common geometry and hydraulic computations...
The Economics of Social Security. ... Many married women in the labor force are eligible for benefits (based on the earnings of their spouse) that are approximately equal to, or in some cases greater than, benefits based on their own...
Draw the absorption spectrum of chlorophyll and compare it to the action spectrum of photosynthesis. Define the Reaction Centers and Antennae and describe how it operates. Describe cyclic photophosphorylation of photosynthesis. Describe noncyclic photophosphorylation of photosynthesis.
Faith 7: Recalling the actions of Rabbi Eliahou's son, Elie prays to the God he no longer believes in, that he have the strength to never do what the rabbi's son had done in abandoning his father. Rabbi Eliahou's search...
Problem: Middleboxes. Try to simplify handshake. Middleboxes do not recognize TLS 1.3. Redesign: make handshake more similar to previous handshake versions. Support. OpenSSL 1.1.1 (when available) Mozilla Firefox, Google Chrome .
Evolution of birds. Smithsonian Museum, Washington, DC. Archaeopteryx. lived about 150 mya. links reptiles & birds. The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the...
Ready to download the document? Go ahead and hit continue!