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Tuesday, June 18, 2013

Command Mode Hierarchy


commands that enable access to e
commands that enable access to each mode and the command-line prompt for each mode.
Command Modes and Prompts
Mode Name
Commands Used to Access
Command-Line Prompt
exec
(user logon)
# or >
access control list ip access-list and policy access-list commands from context  configuration mode (config-access-list)#
ACL condition condition time-range command from access control list  configuration mode (config-acl-condition)#
AS path list
as-path-list command from context configuration mode
(config-as-path-list)#
AT M  D S- 3
port atm command from global configuration mode (config-atm-ds3)#
AT M  O C
port atm command from global configuration mode
(config-atm-oc)#
ATM PVC
atm pvc command from ATM DS-3 and ATM OC configuration modes (config-atm-pvc)#
AU-3
au3 command from STM-1 configuration mode
(config-au3)#
BFD interface
interface command from BFD router configuration mode (config-bfd-if)#
BFD neighbor
neighbor command from BFD router configuration mode
(config-bfd-nbr)#
BFD router router bfd command from context configuration mode
(config-bfd)#
BGP address family
address-family command from BGP router configuration mode (config-bgp-af)#
BGP neighbor
neighbor command from BGP router configuration mode
(config-bgp-neighbor)#
BGP neighbor address family
address-family command from BGP neighbor configuration mode
(config-bgp-af)#
BGP peer group
peer-group command from BGP router configuration mode (config-bgp-peer-group)#
BGP peer group address family
address-family command from BGP peer group configuration mode
(config-bgp-peer-af)#
BGP router
router bgp command from context configuration mode (config-bgp)#
bridge
bridge command from context configuration mode
(config-bridge)#
bridge profile
bridge profile command from global configuration mode (config-bridge-profile)#
community list
community-list command from context configuration mode (config-community-list)#
context
context command from global configuration mode
(config-ctx)#
dot1q PVC
dot1q pvc command from port configuration mode
(config-dot1q-pvc)#
DS-0
port ds0s command from global configuration mode
(config-ds0s)#
DS-1
port ds1 command from global configuration mode
(config-ds1)#
DS-3
port ds3 and port channelized-d3 commands from global  configuration modes
(config-ds3)#
DVSR profile
dvsr-profile command from context configuration mode (config-dvsr)#
E1
port e1 command from global configuration mode
(config-e1)#
E3
port e3 command from global configuration mode
(config-e3)#

Command Mode Hierarchy


Command Modes and Prompts
Command Modes and Prompts
Mode Name
Commands Used to Access
Command-Line Prompt
RIPng router
router ripng command from context configuration mode (config-ripng)#
route map
route-map command from context configuration mode (config-route-map)#
RSVP explicit route
explicit-route command from RSVP router configuration mode (config-rsvp-explicit-route)#
RSVP interface
interface command from RSVP router configuration mode
(config-rsvp-if)#
RSVP LSP
lsp command from RSVP router configuration mode
(config-rsvp-lsp)#
RSVP router router rsvp command from context configuration mode
(config-rsvp)#
STM-1
port channelized-stm1 command from global configuration mode
(config-stm1)#
subscriber
subscriber command from context configuration mode
(config-sub)#
VPLS
vpls command from bridge configuration mode
(config-vpls)#
VPLS profile
vpls profile command from global configuration mode
(config-vpls-profile)#
VPLS profile neighbor neighbor command from VPLS profile configuration mode
(config-vpls-profile-neighbor)#
VRRP
vrrp command from interface configuration mode
(config-vrrp)#
The sham-link and virtual-link commands are available in OSPF area configuration mode for VPN-enabled contexts only.

Command Mode Hierarchy


Command Modes and Prompts
Command Modes and Prompts
Mode Name
Commands Used to Access
Command-Line Prompt
Frame Relay PVC
frame-relay pvc command from DS-0, DS-1, DS-3, E1, E3, and port  configuration modes (config-fr-pvc)#
global
configure command from exec mode
(config)#
IGMP service profile igmp service-profile command from context configuration mode (config-igmp-service-profile)#
interface
interface command from context configuration mode
(config-if)#
IP prefix list
ip prefix-list command from context configuration mode
(config-prefix-list)#
IPv6 prefix list
ipv6 prefix-list command from context configuration mode
(config-ipv6-prefix-list)#
IS-IS address family
address-family command from IS-IS router configuration mode (config-isis-af)#
IS-IS interface
interface command from IS-IS router configuration mode
(config-isis-if)#
IS-IS interface address family
address-family command from IS-IS interface configuration mode (config-isis-if-af)#
IS-IS router
router isis command from context configuration mode (config-isis)#
L2VPN
l2vpn command from context configuration mode
(config-l2vpn)#
L2VPN LDP l2vpn ldp command from L2VPN configuration mode (config-l2vpn-ldp)#
L2VPN static
l2vpn static command from L2VPN configuration mode (config-l2vpn-static)#
LDP router
router ldp command from context configuration mode (config-ldp)#
MPLS interface interface command from MPLS router configuration mode (config-mpls-if)#
MPLS router
router mpls command from context configuration mode (config-mpls)#
MPLS static interface
interface command from MPLS static router configuration mode (config-mpls-static-if)#
MPLS static LSP
lsp command from MPLS static router configuration mode (config-mpls-static-lsp)#
MPLS static router router mpls-static command from context configuration mode (config-mpls-static)#
MSDP peer
peer command from MSDP router configuration mode (config-msdp-peer)#
MSDP router
router msdp command from context configuration mode
(config-msdp)#
OSPF area
area command from OSPF router configuration mode (config-ospf-area)#
OSPF interface
interface command from OSPF area configuration mode
(config-ospf-if)#
OSPF router
router ospf command from context configuration mode (config-ospf)#
OSPF sham link
sham-link command from OSPF area configuration mode1 (config-ospf-sham-link)#
OSPF virtual link
virtual-link command from OSPF area configuration mode1 (config-ospf-virt-link)#
OSPF3 area
area command from OSPF3 router configuration mode
(config-ospf3-area)#
OSPF3 interface interface command from OSPF3 area configuration mode (config-ospf3-if)#
OSPF3 router
router ospf3 command from context configuration mode (config-ospf3)#
port
port ethernet, port channelized oc-12, and port pos commands  from global configuration mode
(config-port)#
RIP interface
interface command from RIP router configuration mode (config-rip-if)#
RIP router
router rip command from context configuration mode
(config-rip)#
RIPng interface
interface command from RIPng router configuration mode (config-ripng-if)#
-->

Monday, June 17, 2013

Router Configuration


Command Modes and Prompts
Mode Name
Commands Used to Access
Command-Line Prompt
Frame Relay PVC
frame-relay pvc command from DS-0, DS-1, DS-3, E1, E3, and port  configuration modes (config-fr-pvc)#
global
configure command from exec mode
(config)#
IGMP service profile igmp service-profile command from context configuration mode (config-igmp-service-profile)#
interface
interface command from context configuration mode
(config-if)#
IP prefix list
ip prefix-list command from context configuration mode
(config-prefix-list)#
IPv6 prefix list
ipv6 prefix-list command from context configuration mode
(config-ipv6-prefix-list)#
IS-IS address family
address-family command from IS-IS router configuration mode (config-isis-af)#
IS-IS interface
interface command from IS-IS router configuration mode
(config-isis-if)#
IS-IS interface address family
address-family command from IS-IS interface configuration mode (config-isis-if-af)#
IS-IS router
router isis command from context configuration mode (config-isis)#
L2VPN
l2vpn command from context configuration mode
(config-l2vpn)#
L2VPN LDP l2vpn ldp command from L2VPN configuration mode (config-l2vpn-ldp)#
L2VPN static
l2vpn static command from L2VPN configuration mode (config-l2vpn-static)#
LDP router
router ldp command from context configuration mode (config-ldp)#
MPLS interface interface command from MPLS router configuration mode (config-mpls-if)#
MPLS router
router mpls command from context configuration mode (config-mpls)#
MPLS static interface
interface command from MPLS static router configuration mode (config-mpls-static-if)#
MPLS static LSP
lsp command from MPLS static router configuration mode (config-mpls-static-lsp)#
MPLS static router router mpls-static command from context configuration mode (config-mpls-static)#
MSDP peer
peer command from MSDP router configuration mode (config-msdp-peer)#
MSDP router
router msdp command from context configuration mode
(config-msdp)#
OSPF area
area command from OSPF router configuration mode (config-ospf-area)#
OSPF interface
interface command from OSPF area configuration mode
(config-ospf-if)#
OSPF router
router ospf command from context configuration mode (config-ospf)#
OSPF sham link
sham-link command from OSPF area configuration mode1 (config-ospf-sham-link)#
OSPF virtual link
virtual-link command from OSPF area configuration mode1 (config-ospf-virt-link)#
OSPF3 area
area command from OSPF3 router configuration mode
(config-ospf3-area)#
OSPF3 interface interface command from OSPF3 area configuration mode (config-ospf3-if)#
OSPF3 router
router ospf3 command from context configuration mode (config-ospf3)#
port
port ethernet, port channelized oc-12, and port pos commands  from global configuration mode
(config-port)#
RIP interface
interface command from RIP router configuration mode (config-rip-if)#
RIP router
router rip command from context configuration mode
(config-rip)#
RIPng interface
interface command from RIPng router configuration mode (config-ripng-if)#

Routing Protocols Configuration Guide

Network routing moves information across an internetwork from a source to a destination, typically passing
through one or more intermediate nodes along the way. The primary difference between routing and
bridging is that the two access different levels of information to determine how to transport packets from
source to destination—routing occurs at layer 3 (the network layer), while bridging occurs at layer 2 (the
link layer) of the Open Systems Interconnection (OSI) reference model.
In addition to transporting packets through an internetwork, routing involves determining optimal paths to
a destination. Routing algorithms use metrics, or standards of measurement, to establish these optimal
paths, initializing and maintaining routing tables that contain all route information.
The SmartEdge OS routing table stores routes to directly attached devices, static IP routes, and routes
learned dynamically from the Routing Information Protocol (RIP), the Open Shortest Path First (OSPF)
protocol, the Border Gateway Protocol (BGP), and the Intermediate System-to-Intermediate System
(IS-IS) routing protocol. In the routing table, next-hop associations specify that a destination can be reached
by sending packets to a next-hop router located on an optimal path to the destination. Routing algorithms
must converge rapidly; that is, all routers must agree on optimal routes.
When a network event causes routes either to go down or become unavailable, routers distribute routing
update messages that are propagated across networks, causing a universally agreed recalculation of optimal
routes. Routing algorithms that converge slowly can cause routing loops or network outages. Many
algorithms can quickly select next-best paths and adapt to changes in network topology.
Methods for implementing IP routing, and the protocols used, are described in the following sections:
• Static Versus Dynamic Routing
• IGPs Versus EGPs
• Supported IP Routing Protocols and Routing-Related Features
• Protocol Distances

Static Versus Dynamic Routing
Static routing involves packet forwarding on the basis of static routes configured by the system
administrator. Static routes work well in environments where network traffic is relatively predictable and
network topology is relatively simple.
In contrast, dynamic routing algorithms adjust to changing network circumstances by analyzing incoming
routing update messages. RIP, OSPF, BGP, and IS-IS all use dynamic routing algorithms. A dynamic
routing algorithm can also be supplemented with static routes where appropriate. For example, a router of
last resort (to which all unroutable packets are sent) can store information on such packets for
troubleshooting purposes.
Some routing algorithms operate in a flat, hierarchy-free space, while others use routing hierarchies. In a
flat routing system such as RIP, all routers are peers of all other routers. As networks increase in size, flat
routing systems encounter scaling limitations. To address this, some routing protocols allow the
administrator to partition the network into hierarchical levels, which facilitates the summary of topology
information for anyone located outside the immediate level or area. An example is the OSPF protocol,
which supports a two-level hierarchy where area 0 is the backbone area that interconnects all other areas.
IGPs Versus EGPs
Another group of protocols that works to optimize network performance are the Interior Gateway Protocols
(IGPs). These optimize the route between points within a network. Examples of commonly used IGPs are
RIP, OSPF, and IS-IS.
Exterior Gateway Protocols (EGPs) support route information exchange between different networks. An
example of a commonly used EGP is BGP-4. The choice of an optimal path is made based on the cost of
the path measured by metrics associated with each link in the network.
IGPs and EGPs have slightly differing administrative designs. An IGP typically runs in an area under a
single administrative control; this area is referred to as an autonomous system (AS) or a routing domain. In
contrast, an EGP allows two different autonomous systems to exchange routing information and send data
across the AS border. Policy decisions in EGPs can be shaped to decide which routing information crosses
the border between the two autonomous systems.
Supported IP Routing Protocols and Routing-Related Features
Redback® currently supports the following IP routing protocols and routing-related features:
• Basic IP Routing
• Dynamically Verified Static Routing
• Virtual Router Redundancy Protocol
• Routing Information Protocol
• Open Shortest Path First
• Bidirectional Forwarding Detection
• Border Gateway Protocol
• Border Gateway Protocol/Multiprotocol Label Switching Virtual Private Network
• Intermediate System-to-Intermediate System Routing
• IP Multicast
• Routing Policy
• Multiprotocol Label Switching
• Layer 2 Virtual Private Network
• Label Distribution Protocol
• Virtual Private LAN Services
Basic IP Routing
Basic IP routing includes static IP routing and other basic routing features not covered by any routing
protocol, including router IDs, static routes for multicast reverse path forwarding (RPF) lookup, IP Martian
addresses, unicast RPF checks, maximum IP routes, and intercontext static routing among non-local
contexts.
Dynamically Verified Static Routing
Dynamically verified static routing (DVSR) is a semidynamic and semistatic routing protocol used mainly
for making edge routing decisions.
SmartEdge routers support DVSR as a unique edge routing feature in addition to static routing and regular
IGPs, such as IS-IS, OSPF, and RIP. DVSR is similar to normal static routing. The main difference is that
the DVSR’s next hop, or some other relevant host IP address, is dynamically verified by this protocol before
the prefix can be injected into the local routing table. In many ISP networks, using static routing without
proper next-hop checks results in blackholing of network traffic.
Virtual Router Redundancy Protocol
Virtual Router Redundancy Protocol (VRRP) eliminates the single point of failure that is common in the
static default routed environment and provides a higher availability default path without requiring the
configuration of dynamic routing or router discovery protocols on every end host.
VRRP works by dynamically assigning responsibility for a virtual router to one of the VRRP routers on a
LAN. A virtual router is defined by its virtual router ID (VRID) and a set of IP addresses. There are two
types of VRRP routers—owner and backup. The VRRP router controlling the IP addresses associated with
a virtual router is called the owner, and it forwards packets sent to the IP addresses.
Routing Information Protocol
RIP is a distance-vector protocol that uses a hop count as its metric. Relatively old, RIP is still commonly
used, especially in small homogeneous networks. Our implementation supports RIP Version 2 and provides
for multiple RIP instances. Each instance maintains its own routing table and set of interfaces. Each
interface can only be assigned to at most one RIP instance.

Open Shortest Path First
OSPF is an IGP that uses link-state advertisements (LSAs) to inform other routers of the state of the
sender’s links. In a link-state routing protocol, each router distributes information about its interfaces and
neighbor relationships. The collection of the link states of individual routers forms a database that describes
the AS topology. As OSPF routers accumulate link-state information, they use the Shortest Path First (SPF)
algorithm to calculate the shortest path to each node, which forms the basis for developing routing
information for that autonomous system.
Bidirectional Forwarding Detection
Bidirectional Forwarding Detection (BFD) is a simple Hello protocol that in many respects is similar to the
detection components of some routing protocols. A pair of routers periodically transmit BFD packets over
each path between the two routers, and if a system stops receiving BFD packets after a predefined time
interval, some component in that particular bidirectional path to the neighboring router is assumed to have
failed.
A path is only declared to be operational when two-way communication has been established between
systems.
BFD provides low overhead, short-duration detection of failures in the path between adjacent forwarding
engines, including the interfaces, data links, and to the extent possible, the forwarding engines themselves.
The legacy Hello mechanism run by routing protocols do not offer detections of less than one second, and
for some applications, more than one second is too long and represents a great deal of lost data at gigabit
rates. BFD provides the ability to detect communication failures in less than one second.
Border Gateway Protocol
Border Gateway Protocol (BGP) is an EGP based on distance-vector algorithms, and uses the Transmission
Control Protocol (TCP) as its transport protocol. BGP is a protocol between exactly two BGP nodes, or
BGP speakers. First, the TCP connection is established and then the two BGP speakers exchange dynamic
routing information over the connection. The exchange of messages is a BGP session between BGP peers.
Border Gateway Protocol/Multiprotocol Label Switching Virtual Private Network
In its most general definition, a Virtual Private Network (VPN) is a network in which customer connectivity
among multiple remote sites is deployed across a shared central infrastructure, yet still provides the same
access or security as a private network.
More specifically, a Border Gateway Protocol/Multiprotocol Label Switching Virtual Private Network
(BGP/MPLS VPN) is a collection of policies, and these policies control connectivity among a set of sites.
A customer site is connected to the service provider network, often called a backbone, by one or more ports,
where the service provider associates each port with a VPN context.
BGP/MPLS VPN allows you to implement a wide range of policies; for example, within a given VPN, you
can allow every site to have a direct route to every other site (full mesh), or you can restrict certain pairs of
sites from having direct routes to each other (partial mesh).
Intermediate System-to-Intermediate System Routing
IS-IS routing is an IGP that uses link-state information to make routing decisions.
IS-IS is defined in ISO 10589, Intermediate System to Intermediate System Intra-Domain Routing
Exchange Protocol for Use in Conjunction with the Protocol for Providing the Connectionlessmode
Network Service (ISO 8473), ISO DP 10589, February 1990, and RFC 1195, Use of OSI IS-IS for Routing
in TCP/IP and Dual Environments.

IP Multicast
IP multicast communication enables a source host to send IP packets to any number of hosts, anywhere
within an IP network; it is one-to-any communication. That is, multicast communication is not limited to
sending packets to a single destination host, or sending packets to every host on the network. Instead,
multicast enables a source host to send IP packets to as many destination hosts as necessary, but no more
than that. The advantages of multicast communication, unlike broadcast communication, which floods the
network with unnecessary traffic, is that a source host can communicate with more than one destination
host without sending traffic to every host on the network. This results in an economic use of bandwidth.
The main challenge for multicast communication is developing a method for determining which hosts will
receive multicast traffic, and which hosts will not receive the traffic. Several different multicast protocols
have been developed, each with its own unique approach to addressing the multicast challenge. The
SmartEdge OS supports the following multicast protocols:
• Internet Group Management Protocol
• Protocol Independent Multicast Sparse Mode
• Multicast Source Discovery Protocol
Routing Policy
Routing policies allow network administrators to enforce various routing policy decisions onto incoming,
outgoing, and redistributed routes. The tools used to configure routing policies include BGP AS path lists,
BGP community lists, IP prefix lists, and route maps with match and set conditions.
Multiprotocol Label Switching
MPLS is a method for efficiently forwarding packets through a network. MPLS operates across an interface
in an MPLS-enabled context.
In a conventional IP network, routers forward packets through the network, from one router to the next,
with each router making an independent forwarding decision by analyzing the packet header. This
conventional approach to forwarding packets has become insufficient to support current networking
demands.
With MPLS, the complete analysis of the packet header is performed only once, when it enters an
MPLS-enabled network. At each incoming (ingress) point of the network, packets are assigned a label by
an edge LSR. Packets are forwarded along a LSP where each LSR makes forwarding decisions based on
the label information. At each hop, the LSR swaps the existing label for a new label that tells the next hop
how to forward the packet. At the outgoing (egress) point, an edge LSR removes the label, and forwards
the packet to its destination. MPLS uses the Resource Reservation Protocol (RSVP), or the LDP, to
communicate labels and their meaning among LSRs.

Layer 2 Virtual Private Network
Layer 2 Virtual Private Networks (L2VPNs) customer edge (CE) routers send L2 traffic to provider edge
(PE) routers over L2 circuits configured between the PE and the CE routers. An L2 circuit can be either an
Ethernet port, an 802.1Q virtual LAN (VLAN), a Frame Relay permanent virtual circuit (PVC), or an
Asynchronous Transfer Mode (ATM) PVC.
An L2VPN is configured on PE routers and is used to cross-connect a local L2 circuit with a corresponding
remote L2 circuit through an LSP tunnel that crosses the network backbone.
Label Distribution Protocol
LDP enables dynamic label allocation and distribution in an MPLS network. An LSR enabled with LDP
can establish LSPs to other LSRs in the network. LDP creates label bindings by assigning labels to
connected routers and by advertising the bindings to neighbors. LDP also assigns labels to label bindings
learned from neighbors, and readvertises the binding to other neighbors. When an LSR advertises a label
binding for a route, the LSR is advertising the availability of an LSP to the destination of that route. LDP
can learn several LSPs from different neighbors for the same route. In this case, LDP activates only the path
selected by the underlying IGP. For this reason, LDP must work together with an IGP, such as the IS-IS or
OSPF protocol.
Virtual Private LAN Services
VPLS enables networks at separate geographical locations to communicate with each other across a wide
area network (WAN) as if they were directly attached to each other in a LAN. The WAN becomes
transparent, which is achieved by creating VPLS pseudo-wires.
A pseudo-wire is a mechanism that emulates the attributes and function of Ethernet connectivity over a
WAN. Any required switching functionality or service translation is outside the scope of the pseudo-wire
and of the transport network. Pseudo-wires are carried over MPLS tunnels on the network.
MPLS signaling protocols are used to automatically provision a service on a pseudo-wire end-to-end, so
you can provision a pseudo-wire by pointing to its two endpoints, and MPLS automatically negotiates the
path.
Protocol Distances
When determining a single optimal route among multiple routes within a single routing protocol, the
SmartEdge OS selects the route that has the shortest distance. When deciding a best path among routes
originating from multiple protocols, the system uses a more complex methodology. The SmartEdge routing
table stores direct, static, external BGP (eBGP), OSPF, IS-IS, RIP, and internal BGP (iBGP) routes.

Table 1-1 lists the protocols and their default values for routes learned through various protocols.
Command Mode Hierarchy
Command modes exist in a hierarchy; that is, you must access the higher-level command mode before you
can access a lower-level command mode in the same chain.


Protocol Distance Defaults
Protocol Distance Value
Directly connected 0
Static IP 1
eBGP 20
OSPF 110
IS-IS 115
RIP 120
iBGP 200


Note For modes relevant to basic system features, see the “Overview” chapter in the Basic System
Configuration Guide for the SmartEdge OS. For modes relevant to port, circuit, and tunnel features,
see the "Overview" chapter in the Ports, Circuits, and Tunnels Configuration Guide for the
SmartEdge OS. For modes relevant to IP services and security features, see the “Overview” chapter
in the IP Services and Security Configuration Guide for the SmartEdge OS.