9. Re-establishing Logical Communication September 19-22 2010 Mission Critical Network Design Seminar A B E C D PC1 PC2 Device Path Port 1 PC1 Port 1 Port 2 PC1 Port 2 Learned Address Table Switch “D”
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12. Graph Theory September 19-22 2010 Mission Critical Network Design Seminar Spanning Tree Graph
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31. Multiple Rings September 19-22 2010 Mission Critical Network Design Seminar Base Ring RM SRM SRM SRM SRM RM – Redundancy Manager SRM – Sub-ring Manager
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43. Layer 2 Bridging – Pipeline Example September 19-22 2010 Mission Critical Network Design Seminar Enable RSTP
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52. Virtual Router Redundancy Protocol – VRRP (RFC 3768) September 19-22 2010 Mission Critical Network Design Seminar Master Backup 192.168.0.1 10.0.0.1 Virtual IP address and MAC address 192.168.0.0/24 10.0.0.0/24
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54. EAGLE Redundancy (Layer 3) September 19-22 2010 Mission Critical Network Design Seminar Master Slave Virtual IP and MAC addresses Exchange connection state tables HIRSCHMANN HIRSCHMANN 192.168.0.0/24 10.0.0.0/24
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57. RIP Routing Tables September 19-22 2010 Mission Critical Network Design Seminar Stuttgart A 1 hop N/A B 1 hop N/A C 2 hops Frankfurt D 2 hops Frankfurt E 2 hops Munich F 2 hops Frankfurt G 3 hops Frankfurt H 3 hops Frankfurt
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59. Shortest Path First Algorithm September 19-22 2010 Mission Critical Network Design Seminar Frankfurt Munich 0 Stuttgart Leipzig 188 305 367 Hannover 585 Berlin 512
63. September 19-22 2010 Mission Critical Network Design Seminar Zero failover – duplicated networks Outlook: PRP (Parallel Redundancy Protocol ) Data is sent on both networks simultaneously DANP - Dual attached node implementing PRP SAN - Single attached nodes (Source: IEC 62439)
64. September 19-22 2010 Mission Critical Network Design Seminar Zero failover Redundant Ring Outlook: HSR ( High availability Seamless Ring) (Source: IEC SC65C WG15 / TC57 WG10, H. Kirrmann)
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Editor's Notes
All the routers within a network on which VRRP is active specify among themselves which router is to be the master. This router contains the IP and MAC address of the virtual router. All the devices in the network that have entered this virtual IP address as the default gateway use the master as the default gateway. If the master fails, then the remaining routers use the VRRP to specify a new master. This router then takes over the IP and MAC address of the virtual router. Thus the devices find their route via their default gateway, as before. The devices always only see the master with the virtual MAC and IP address-es, regardless of which router is actually behind this virtual address. Additionally to the virtual IP address also a virtual MAC address is used, thus improving the recovery time because hosts don’t need to update their ARP cache. The VRRP specifies the virtual MAC address with: 00:00:5e:00:01:<VRID>. The first 5 octets form the fixed part in accordance with RFC 2338. The last octet is the virtual router ID (VRID). It is a number between 1 and 255. On the basis of this, the administrator can define 255 virtual routers with-in a network.
RIP is fast in building-up configuration, but slow in changing states (convergence). As a Distance Vector method it uses the hop count as only criterion (metric) for the routing decision. Routing updates - sent as broadcast every 30 s - propagate its whole routing table to all neighbor router. RIPv2 offers subnetting (propagates the netmask) and authentification with a simple pasword (16 octet) and works with multicasts to 224.0.0.9 instead of BCs. Metric = 0 for itself, and only itself! Direct connected networks have hop count = 1. Maximum 15 hops possible. Value 16 means „not reachable “. Better routes are accepted immediately, similar good and worse routes are ignored (the first of identical best ones is used), deteriorations (cessation of routes) gain acceptance only slowly (count to infinity //16//). Improvement by „split horizon“
After the second update Stuttgart knows now the direct connected networks A and B with hop=1, the next closer networks C, D, E and F with hop=2 and the following networks G and H with hop=3.
OSPF is slow in building-up configuration, but faster than RIP in changing the state (convergence), 5 ... 15 s Periodical hello packets inform about router state Link states transmitted only after changes Link state refresh every 30 minutes Advantages: better selection of path by more flexible metrics redundant connection or load distribution possible hierarchical network architecture possible Per TOS state there is a separate group of routes
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