Packet filters (or in Cisco terminology Access Control Lists aka ACL) are one of the most used tools in a network engineer’s tool set. Blocking telnet/ssh access, restricting specific traffic flows, implementing policy-based routing or NATing – all of these tasks use IP filter’s capabilities.
In this example I’ll show you how to configure basic SSH-blocking IP filter on Alcatel-Lucent Service Routing OS running
TiMOS-B-12.0.R8 both/i386 ALCATEL SR 7750 Copyright (c) 2000-2015 Alcatel-Lucent .
The purpose of this post is to cover basic OSPF configuration steps and commands. Intended readers are engineers with basic OSPF knowledge who want to know how to configure OSPF on Alcatel-Lucent Service Routers (7750-SR, 7705-SR, 7210-SR). All the examples are valid for
TiMOS-B-12.0.R8 both/i386 ALCATEL SR 7750 Copyright (c) 2000-2015 Alcatel-Lucent. software.
When it comes to basic OSPF troubleshooting the first-aid kit is Neighbor states and things, that should match to form an adjacency. And on one early morning while refreshing my memory on OSPF neighbor states I accidentally ran into quite interesting problem.
But before we start, answer the short question:
Will adjacency be formed between directly connected via Gig. Ethernet interfaces routers R1 and R2 if
- R1’s OSPF interface type configured as point-to-point
- R2’s OSPF interface type configured as broadcast
Time’s up. The answer is – yes and no. Wanna know why? Jump in, I have to show you something.
Major network vendors (except Cisco) default to the following modes of Label Distribution Protocol (LDP) operation (as per RFC 5036 LDP Specification):
- Label Distribution (Advertisement): Downstream Unsolicited (section 2.6.3)
- Label Control: Ordered (section 2.6.1)
- Label Retention: Liberal (section 2.6.2)
This topic focuses on Ordered Label Distribution Control procedure to help you better understand when LSR actually assigns labels and initiates transmission of a label mapping.