Hardening Network Infrastructure FS. The Industrial Ethernet Book | Knowledge | Technical Articles | Dual-homing: resilience up to the network's edge. In Ethernet LANs, dual-homing is a network topology that adds reliability by allowing a device to be connected to the network by way of two independent connection points (points of attachment). One access point provides the operating connection while the other implements a standby or back-up connection activated in the event of operating connection failure. A dual-homing switch, with two attachments into the network, offers two independent media paths and two upstream switch connections. Loss of the Link signal on the operating port connected upstream indicates a fault in that path, and traffic is quickly moved to the standby connection so accomplishing fault recovery.
For industrial applications, the most common redundant Ethernet LAN topology is the ring. Although a ring structure will recover from a media break or the failure of a switch, the failure of a switch in the ring takes down the nodes connected into that switch. Some LAN designs use two rings for greater redundancy.
Introduction to Storage Area Networks (SAN) NAS and SAN Introduction. Episode #329: Introduction to Virtualization Infrastructure Design. Understanding Switches. Introduction to Virtualization. Episode #328: Introduction to Type 1 Hypervisor Virtualization - Bare Metal Virtual Servers. Reliability of High Temperature Electronics - A. Christou. High-Temperature Electronics. Volume 46 – April 2012 Download this article in PDF format. (957 KB) High-Temperature Electronics Pose Design and Reliability Challenges By Jeff Watson and Gustavo Castro Introduction Many industries are calling for electronics that can operate reliably in harsh environments, including extremely high temperatures. High-Temperature ApplicationsThe oldest, and currently largest, user of high-temperature electronics (>150°C) is the downhole oil and gas industry (Figure 1).
Figure 1. In the past, drilling operations have maxed out at temperatures of 150°C to 175°C, but declining reserves of easily accessible natural resources coupled with advances in technology have motivated the industry to drill deeper, as well as in regions of the world with a higher geothermal gradient. The applications for high-temperature electronics in the downhole industry can be quite complex. Figure 2. Figure 3. The automotive industry provides another emerging application for use of high-temperature electronics. Router - Best solution for Multi-WAN failover (inside & out)?
Using DNS for failover using multiple A records. Domain Name System. The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates domain names, which can be easily memorized by humans, to the numerical IP addresses needed for the purpose of computer services and devices worldwide. The Domain Name System is an essential component of the functionality of most Internet services because it is the Internet's primary directory service.
The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain. Authoritative name servers are assigned to be responsible for their supported domains, and may delegate authority over sub-domains to other name servers. Function History Structure  Domain name space Simple Failover. Off topic - Low-cost ISP failover for inbound traffic?
How to get two ISP's to work as failover? Virtual Router Redundancy Protocol. The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.
VRRP provides information on the state of a router, not the routes processed and exchanged by that router. Each VRRP instance is limited, in scope, to a single subnet. It does not advertise IP routes beyond that subnet or affect the routing table in any way. VRRP can be used in Ethernet, MPLS and token ring networks with Internet Protocol Version 4 (IPv4), as well as IPv6. Implementation A virtual router must use 00-00-5E-00-01-XX as its Media Access Control (MAC) address.
Routers have a priority of between 1-255 and the router with the highest priority will become the master. The default priority is 100 for backups and 255 for a master. Elections of master routers Configuring 1+1 Backup by High Availability (HA) – Peplink Knowledgebase. 1+1 Backup requires a pair of Peplink Balance devices or MAX 700/HD, operating in active-standby mode.
When the master device is down, the slave device takes over and handles all the LAN traffic. Peplink Balance 210 or above, MAX 700/HD support High Availability (HA) failover between two Balance/MAX devices based on Virtual Router Redundancy Protocol (VRRP). Periodic VRRP advertisement packets are sent out from the master device to VRRP-specific IP multicast addresses. The slave device assumes the master device’s responsibilities when these messages have not been heard from for a pre-defined time interval. Network Setup Example in NAT mode Achieve Ultimate Network Uptime with Peplink Balance In the above example, a HA Group 20 is assigned to the HA pair. Additional Ethernet switches are required to separate each ISP connection so that Master and Slave Balance devices can both be connected. Configuring High Availability Configuration for 1+1 Backup in NAT mode HA for Master Configuration. Cradlepoint ARC MBR1400 Series Branch Router with Integrated 3G/4G | Cradlepoint.
Most ARC MBR1400 models come with an integrated modem included – see available models below. A version with no integrated modem is available for use with USB/ExpressCard modems. Click here to view compatible external modems. U.S. & Canada Carriers Each MC400 modem includes two 2FF SIM slots. NOTE: LPE models are flexible and support bands for multiple cellular providers; however, only the frequency bands in bold are supported by the listed provider. ARC MBR1400LPE-VZ – 3G/4G Verizon with multi-band LTE Technology: LTE, HSPA+, EVDO Rev ADownlink Rates: LTE 100 Mbps, HSPA+ 21.1 Mbps, EVDO 3.1 Mbps (theoretical)Uplink Rates: LTE 50 Mbps, HSPA+ 5.76 Mbps, EVDO 1.8 Mbps (theoretical)Frequency Bands: LTE Band 2 (1900 MHz), Band 4 – AWS (1700/2100 MHz), Band 5 (850 MHz), Band 13 (700 MHz), Band 17 (700 MHz), Band 25 (1900 MHz) HSPA+/UMTS (850/900/1900/2100 MHz, AWS) GSM/GPRS/EDGE (850/900/1800/1900 MHz) CDMA EVDO Rev A/1xRTT (800/1900 MHz) ARC MBR1400LPE-AT – 3G/4G AT&T with multi-band LTE.
Employing high availability (HA) to improve network reliability.