• Service Provider Routing and Switching Certification Track

    sh configuration,sh ver,show interface terse,show interfaces [intfc] detail,show route,..

    JUNOS Internet Software Configuration Guide: Getting Started


    • It's Different and That's Okay
    • It's Cool
    • FreeBSD UNIX
    • Modular Architecture
    • Independent Process
    • Hierarchy of Design


    • From Branch to Core
    • From Router to Switch to Firewall
    • Same Source Code Base


    • Control is Key
    • Routing Engine (RE)
    • Routing Table (RT)
    • Forwarding Table (FT)
    • Packet Forwarding Engine (PFE)
    • Completely Separate Planes


    • Is the Intelligence of the Platform
    • Routing Tables
    • Bridging Table
    • Primary Forwarding Engine


    • ASIC Based
    • Forwarding Table Copy
    • It does the Leg Work

    The Junos OS CLI compare with Cisco
    The Basics:

    • % cli = ena
    • > edit / configure = conf t
    • # load factory-default = wr era
    • # set system root-authentication plain-text-password = username root password
    • # show system = sho run
    • # show system | display set
    • # show interface | display set = sho ip int bri
    • # show configuration | display set

    Platforms Running the Junos OS

    • M Series Multiservice Routers can be deployed in both high-end enterprise and service-provider environments.
    • T Series Core Routers is ideal for service provider environments and is deployed within the core of those networks.
    • J Series Services Routers are deployed at a branch and remote locations in the network.
    • MX Series Ethernet Services Routers is targeted for dense dedicated access aggregation and provide edge services in medium and large POPs.
    • EX Series Ethernet Switches are designed for access, aggregation, and core deployments and are well for enterprise and data center.
    • SRX Series Services Gateways is designed to meet the network and security in both enterprise and service provider environments.

    • The Junos OS is compartmentalized into multiple software processes. Each process runs in its own protected memory space, ensuring that one process cannot directly interfere with another. This modularity also ensures that new features can be added with less likelihood of breaking current functionality are some advantages of the Junos OS.

    • The primary functions of the control plane are to maintain routing intelligence, control and monitor the chassis, and manage the Packet Forwarding Engine (PFE). The primary functions of the forwarding plane are to forward packets and to implement advanced services.

    • Transit traffic is forwarded through the PFE on platforms running the Junos OS, based on the forwarding table installed on the PFE. Exception traffic is processed locally by the platform running the Junos OS by either the PFE or the RE depending on the type of traffic. Host-bound packets, such as protocol and management traffic, are passed directly to the RE for processing, while traffic requiring ICMP error message responses is typically handled by the PFE.

    • > ?
    • > clear ?

    • > help topic interfaces ?
    • > help topic interfaces address

    • > help reference interfaces address

    • edit - functions like a CD command
    • up - moves up one level
    • up n - moves up n levels
    • top - moves to the top of the hierarchy
    • exit - moves to the previous, higher level in the hierarchy or exits configuration mode if at the top level of the hierarchy

    • Two primary modes exist within the Junos OS: the operational mode and the configuration mode. A third mode also exists in the form of the FreeBSD shell.
      Type configure at the operational mode prompt to enter configuration mode:

    • Use the operational mode to monitor and troubleshoot the software, network connectivity, and hardware. Use the configuration mode to configure a device running the Junos OS, including interfaces, protocols, user access, and system hardware.

    • Use the Spacebar to complete a command and the Tab key to complete a variable.

    • The top command is the quickest method of returning to the top of the hierarchy.

    • The active configuration has been committed and is in use, whereas the candidate configuration is not active until performing a commit operation.

    • The show | compare command displays the differences between the currently active and candidate configurations.


    Juniper Networks Certified Internet Associate (JNCIA) Study Guide
    Juniper Networks Certified Internet Professional (JNCIP) Study Guide
    Juniper Networks Certified Internet Expert (JNCIE) Study Guide

    • The Routing Engine is the intelligence of the router. It operates the routing protocols and builds a routing and forwarding table. The forwarding table is copied to the Packet Forwarding Engine, where the actual transmission of user data packets is handled.

    • The JUNOS software is stored on the internal flash drive, the internal hard drive, and the removable flash media. When the router begins to boot, the removable media is checked first, followed by the internal flash drive, and finally the internal hard drive.

    • May save the router's configuration to the hard drive with the save command. The load command restores files to the candidate configuration. The candidate configuration becomes the active configuration with the commit command. Can easily return to a previous configuration with the rollback command.

    • There are four main ASICs used in the Packet Forwarding Engine: the Internet Processor ASIC, the Distributed Buffer Manager ASIC, the I/O Manager ASIC, and the PIC I/O Manager ASIC.

    A packet is received on an interface (1,2) and is segmented into J-cells by the I/O Manager ASIC (3). The Distributed Buffer Manager ASIC stores the packet in the shared memory pool (4-6). The Internet Processor ASIC performs a route lookup (7) and sends the result to the Distributed Buffer Manager ASIC (8), which forwards it to the outgoing I/O Manager ASIC (9). After queuing the packet, the I/O Manager ASIC receives the J-cells from the memory pool (10) and re-forms the packet (11). It is sent to the outgoing PIC I/O Manager ASIC for transmission into the network (12).
  • 3 Comments sorted by
    • An exception packet could be a routing protocol update, a locally addressed packet, or a packet requiring the generation of an ICMP error message. The CPU on the router's control board handles these exception packets and performs the appropriate action.

    • Operates routing protocols, loads the JUNOS software, and controls the CLI are the functions of the Routing Engine.
      The Routing Engine performs multiple functions, including operating the routing protocols on the router, loading the JUNOS software, and controlling the CLI. The Packet Forwarding Engine controls packet forwarding.

    • Routing Engine router component is responsible for creating the forwarding table.
      The Routing Engine builds the master routing table, selects the best path to each route, and places those next hops into the forwarding table.

    • The PIC I/O Manager ASIC is responsible for transmitting packets function.
      The PIC I/O Manager ASIC is responsible for receiving and transmitting data packets from the physical media connected to the PIC.

    • The Internet Processor ASIC is responsible for performing route lookups function.
      The Internet Processor ASIC consults the forwarding table on the control board to determine the next-hop router along the path to the destination.

    • The I/O Manager ASIC is responsible for creating J-cells function.
      The I/O manager ASIC is responsible for multiple functions in the router. One of those is the creation of J-cells from the original data packet.

    • The Distributed Buffer Manager ASIC is responsible for storing packets in memory function.
      The primary role of the Distributed Buffer Manager ASIC is storing and retrieving J-cells from the packet storage buffer.

    • A unicast packet is flowing through the Packet Forwarding Engine. Incoming I/O Manager ASIC receives the packet after the incoming PIC I/O Manager ASIC performs its functions.
      After receiving the packet from the physical media and performing any link-layer functions, the incoming PIC I/O Manager ASIC sends the packet to the incoming I/O Manager ASIC on its FPC.

    • Switching control board CPU component of the router is responsible for handling exception packets.
      The CPU on the router's control board is responsible for handing exception packets. Some of those exception packets might reach the Routing Engine.

    • IP packets with TTL=1 and Routing protocol updates are considered exception packets.
      Routing protocol updates and packets requiring an ICMP error message (TTL=1) are considered exception packets. A Juniper Networks router does not communicate using the HTTP or SMTP protocols. Therefore, these packets must be transiting the router and are handled by the Packet Forwarding Engine.

    • mgd JUNOS software daemon is responsible for operating the CLI.
      The Management Daemon (mgd) is responsible for controlling the CLI process.

    • rpd JUNOS software daemon is responsible for controlling the routing protocols.
      The Routing Protocol Daemon (rpd) is responsible for all routing protocol activity on the router.

    • When issued from the top of the configuration hierarchy, save saved-file command creates a file called saved-file that contains the entire candidate configuration.
      The save command takes portions of the candidate configuration and places them in a file you specify. When used from the top of the hierarchy, this process saves the entire candidate configuration.

    • rollback 5 command places the juniper.conf.5.gz file in the candidate configuration.
      load override juniper.conf.5.gz and load merge juniper.conf.5.gz will look for the juniper.conf.5.gz file in the user's home directory, where it is not stored by default.

    • /var/home is the router store each user's home directory.
      Each user configured on the router receives his or her own home directory in the /var/home section of the hard drive.

    • Internal flash drive is the primary boot media for the JUNOS software.
      The router's internal flash drive is the primary boot location for the JUNOS software.

    • Internal hard drive is the secondary boot media for the JUNOS software.
      The router's internal hard drive is the secondary boot location for the JUNOS software.

    • request system software add filename command loads a new version of the JUNOS software into the internal flash drive.
      The request system software add filename command loads a copy of the JUNOS software onto the router's flash drive.

    • Ctrl+A Emacs keystroke takes the cursor to the beginning of the command line.
      To reach the beginning of the command line, use the Ctrl+A keystroke. Ctrl+E takes you to the end and Ctrl+W deletes the previous word. Ctrl+D closes your terminal during a load merge terminal operation.

    • load merge terminal command allows you to paste text directly into the candidate configuration.
      The load merge terminal command allows you to cut and paste configuration directly into the router.

    • When committing configuration, commit confirmed command allows the router to automatically return to a previous configuration.
      The commit confirmed command allows the router to return to the previous configuration automatically if don't issue a regular commit within the default 10-minute timer.

    • The format consists of a two-character media type designator followed by the FPC slot number, the PIC slot number within an FPC, the port number on the PIC, and the logical unit. the format is media_type-fpc/pic/port.unit.

    • Each Juniper Networks router contains the fxp0 and fxp1 permanent interfaces. All interfaces contained on a PIC are considered transient because they can be removed at any time.

    • The inet, inet6, iso, and mpls protocol families are configurable on a Juniper Networks interface.

    • Each interface in the JUNOS software requires some logical properties. These often include the Layer 3 and Layer 2 addressing information for enabling proper network operation.

    • The show interfaces extensive command, information such as the current status, input/output byte and packet statistics, and input/output error counters are available in the command output.

    • Both loopback and BERT testing help to locate trouble spots on a physical network circuit.

    • Type, FPC, PIC, and port is the order of elements in the JUNOS software interface naming convention.
      The order is the media type, FPC slot number, PIC slot number, and PIC port number.

    • 0 through 7, left to right are the FPC slot numbers for an M40e numbered.
      An M40e has eight vertical FPC slots. They are numbered 0 through 7, left to right.

    • 0 through 3, right to left are the PIC slots numbered on an M20 FPC.
      An M20 has four PIC slots in each FPC. Since the FPC has a horizontal orientation, the PIC slots are numbered 0 through 3, right to left.

    • Permanent and transient are two different types of interfaces on a Juniper Networks router.
      Juniper Networks routers have two types of interfaces: permanent and transient.

    • Keepalives, Description, and FCS are the example of a physical interface configuration.
      Only the protocol address is a logical property of an interface.
    • DLCIs number and Protocol MTU are both examples of a logical interface configuration properties.
      Scrambling and description are physical properties.

    • The router assigns a /32 prefix length to an IPv4 address if you do not specify one in the configuration.
      In the absence of a prefix length, the router assumes a 32-bit prefix length for an IPv4 address.

    • show interfaces so-* terse command displays the status of all SONET interfaces on the router.
      An asterisk ( * ) may be used as a wildcard character. The command show interface so-* terse will display the status of all SONET interfaces on the router.

    • An interface has multiple IP addresses configured. The interface's primary address is the lowest numbered address on the interface.
      An interface contains only a single primary address and, by default, it is the lowest numerical prefix on the interface.

    • The configuration is ignored and not applied is the result of using the deactivate command.
      When an interface has been deactivated, the interface is marked inactive and the configuration statements are ignored when the candidate configuration is committed.

    • In the show interfaces extensive output, Input Errors field displays framing errors.
      Input Errors are the sum of the incoming frame aborts and FCS errors.

    • input L3 incompletes field in the show interfaces extensive output displays received packets with a damaged IP header.
      The input L3 incompletes field is a counter that is incremented when the incoming packet fails Layer 3 (usually IPv4) checks of the header.

    • A Frame Relay interface is configured to support DLCI values 40, 50, and 60. Incoming frames show a DLCI 45 at input L2 channel errors field in the show interfaces extensive output.
      The input L2 channel errors field is a counter that increments when the software cannot find a valid logical interface for an incoming frame.

    • Time for a bit of JunOS

    • The Death of TRILL

    • JunOS - The basics

    • JunOS vs IOS - Basic OSPF

    • Recovering the Root Password

    • [EX] While booting up, switch stuck in db> mode

    • สร้าง Client Windows 7 ใน GNS3 โดยใช้ VirtualBox


    • /31's effect on routing protocols

    • Upgrading JUNOS

    • Upgrading the compact flash on a Juniper M10 (RE2.0, RE333)

    • Missing mandatory statement: 'root-authentication'
      root@Olive# set system root-authentication plain-text-password

    • Partition a Juniper router into logical systems

    • First JUNOS logical topology

    • aconaway.com/2012/07/31/junos-basics-configuring-bgp

    • Getting started with JUNOS routing policy

    • JUNOS hard-disk recovery

    Cisco > Juniper command:
    • show bgp vrf B0 ipv4 unicast  neighbor advertised-routes > show route advertising-protocol bgp table B0
    • show bgp vrf B0 ipv4 unicast  neighbor advertised-routes | inc pre > show bgp neighbor instance B0 | match Adv
    • show ip interface brief | include > show interfaces terse | match
    • show run router bgp 69 vrf B0 > show configuration routing-instances B0 protocols bgp group CI

    • The IP address belongs to Class A of IP address space

    • An IPv6 address consists of 128 bits separated into eight 16-bit hexadecimal sections

    • LSPs (MPLS label-switched paths) are unidirectional, can follow paths other than the IGP's shortest path

    • End hosts determine the path MTU for IPv6 and Packet fragmentation occurs at intermediate nodes for IPv4 are two ways that packet fragmentation is handled differently between IPv6 and IPv4

    • Configuring Static Routing:
      # set routing-options static route next-hop
      > show route protocol static   

      inet.0: 39 destinations, 39 routes (39 active, 0 holddown, 0 hidden)
      + = Active Route, - = Last Active, * = Both        *[Static/5] 00:00:06
                          > to via ge-0/0/1.0        *[Static/5] 00:01:05
                          > to via ge-0/0/2.0        *[Static/5] 00:01:05
                          > to via ge-0/0/3.0        *[Static/5] 00:01:05
                          > to via ge-0/0/6.0
      There are four static routes that route traffic through different interfaces.ge-0/0/6 interface does the router use if traffic is sent to the destination

    • 14 host addresses are available in the network

    • Benefits of using IPv6:
      • Supports a greater level of security by integrating features that were optional add-ons in IPv4
      • Reduces administrative overhead using stateless address autoconfiguration for hosts
      • Eliminates the need for private to public NAT using a large address pool

    • The forwarding table is stored on both the RE and PFE