Objectives: As a Brocade Certified vRouter Engineer, you must be able to demonstrate the ability to install, configure and troubleshoot features of Brocade Vyatta Network OS.
Target: This course is for anyone tasked with configuring or managing the Brocade Vyatta vRouter. This course also for those who are preparing to take the BCVRE Certification Exam.
Course prerequisites: Before taking these bundled courses, students should have basic IT networking experience, including working knowledge of TCP/IP.
BCvRE Bootcamp
Agenda:
- End-to-End Packet Flow
- TCP and UDP
- IP Addressing
Daftar Isi
End-to-End Packet Flow
OSI Reference Model
Example details how a packet is routed from Host A to Host B on another
subnet or network address.
- If the destination host’s network number was the same as the source host’s, then the destination host would be considered local and on the same subnet.
- Otherwise the packets will be forwarded to the default gateway in order to be sent to a remote host
If default gateway’s MAC address is not in Host A’s cache. Host A initiates a local ARP broadcast request attempting to resolve the IP address to a physical MAC address.
- Router 1 responds with a unicast ARP response to Host A with its MAC address of 22.
- Host A creates/encapsulates an Ethernet frame with its own MAC 11 as the source and a destination MAC address of 22. Notice the destination IP still remains 192.168.3.20 and the frame can be sent on the wire.
TCP and UDP
TCP (Transmission Control Protocol)
Transmission Control Protocol (TCP) layer 4 protocols used for end-to-end data transmission over IP.
TCP is a connection-oriented protocol. This means that the two end stations establish a connection before exchanging any application data.
- This exchange is called a three-way handshake.
UDP (User Datagram Protocol)
- User Datagram Protocol (UDP) are layer 4 protocols used for end-to-end data transmission over IP.
- UDP is a connectionless protocol.
- End stations do not establish a connection, do not acknowledge packets, and do not perform retransmissions of individual packets.
Welknown Port
IP Addressing
Understanding IP Addresses
An IP address is an address used in order to uniquely identify a device on an IP network.
An IP address consists of 32 bits, which can be divided into two portions: the network, and the host.
A second 32-bit binary number called the network mask determines which bits are which.
When writing an IP address down, the 32 bits are broken down into four octets. Each octet is then converted into a decimal number.
- The four decimal numbers are then separated by a period (dot).
- This format is called dotted decimal format
- for example, 172.16.32.45
OSI Network Layer
IPv4 Header
IPv4 Address Format
IPv4 Address Classes
IPv4 Private Address – RFC 1918
- Used within local networks only (behind routers and firewalls)
- Using NAT (Network Address Translation) technology to route IPv4 Private Address to public network.
Broadcast Address
- Layer 2 broadcasts: These are sent to all nodes on a LAN
- Example: FF.FF.FF.FF.FF.FF
- Broadcasts (layer 3): These are sent to all nodes on the network
- Example: 172.16.255.255
- Unicast: These are sent to a single destination host
- Multicast: These are packets sent from a single source and transmitted to many devices on different networks
- Example: 224.0.0.9 (RIP Multicast), 224.0.0.5 (OSPF Multicast), 224.0.0.10 (EIGRP Multicast).
- Anycast: methodology in which datagrams from a single sender are routed to the topologically nearest node in a group of potential receivers
The Internet Control Message Protocol (ICMP)
- It is used by the operating systems of networked computers to send error messages indicating.
- Ping uses an ICMP echo request datagram testing IP connectivity between hosts.
- Traceroute using ICMP time-outs, Traceroute is used to discover the path a packet takes as it traverses an internetwork.
Address Resolution Protocol (ARP)
- An Internet protocol used to map an IP address to a MAC address. Defined in RFC 826
- When IP has a datagram to send, it must inform a Network Access protocol, such as Ethernet or Token Ring, of the destination’s hardware address on the local network.
ARP table
- A list of IP addresses of neighbors on the same VLAN, along with their MAC addresses, as kept in memory by hosts and routers
Reverse Address Resolution Protocol (RARP)
- RARP resolves Ethernet (MAC) addresses to IP addresses.
- When an IP machine happens to be a diskless machine, it has no way of initially knowing its IP address.
- Discovers the identity of the IP address for diskless machines by sending out a packet that includes its MAC address and a request for the IP address assigned to that MAC address
Proxy Address Resolution Protocol (Proxy ARP)
- A technique by which a device on a given network answers the ARP queries for a network address that is not on that network.
Number of Networks
Size of Network and Host Parts of Class A, B, and C Addresses
AND Operation
ANDING With Custom subnet masks.
Class A IP Address Range Example
| Network Address | 10.0.0.0 |
| Subnet Mask Default | 255.0.0.0 |
| First Valid Host | 10.0.0.1 |
| Last Valid Host | 10.255.255.254 |
| Broadcast Address | 10.255.255.255 |
| Network Address | 00001010.00000000.00000000.00000000 |
| Subnet Mask Default | 11111111.00000000.00000000.00000000 |
| First Valid Host | 00001010.00000000.00000000.00000001 |
| Last Valid Host | 00001010.11111111.11111111.11111110 |
| Broadcast Address | 00001010.11111111.11111111.11111111 |
Class B IP Address Range Example
| Network Address | 172.16.0.0 |
| Subnet Mask Default | 255.255.0.0 |
| First Valid Host | 172.16.0.1 |
| Last Valid Host | 172.16.255.254 |
| Broadcast Address | 172.16.255.255 |
| Network Address | 10101100. 00010000.00000000.00000000 |
| Subnet Mask Default | 11111111.11111111.00000000.00000000 |
| First Valid Host | 00001010.00000000.00000000.00000001 |
| Last Valid Host | 10101100. 00010000.11111111.11111110 |
| Broadcast Address | 10101100. 00010000.11111111.11111111 |
Class C IP Address Range Example
| Network Address | 192.168.0.0 |
| Subnet Mask Default | 255.255.255.0 |
| First Valid Host | 192.168.0.1 |
| Last Valid Host | 192.168.0.254 |
| Broadcast Address | 192.168.0.255 |
| Network Address | 11000000. 10101000.00000000.00000000 |
| Subnet Mask Default | 11111111.11111111.11111111.00000000 |
| First Valid Host | 11000000. 10101000.00000000.00000001 |
| Last Valid Host | 11000000. 10101000.00000000.11111110 |
| Broadcast Address | 11000000. 10101000.00000000.11111111 |
Classless Inter-Domain Routing (CIDR)
- Use to allocate a number of addresses to a company, a home or a customer.
- Example: A Class B default mask would be 255.255.0.0, which is a /16 because 16 bits are ones (1s): 11111111.11111111.00000000.00000000
- The slash notation (/) means how many bits are turned on (1s)
CIDR Value
| Subnet Mask | CIDR Value |
| 255.0.0.0 | /8 |
| 255.128.0.0 | /9 |
| 255.192.0.0 | /10 |
| 255.224.0.0 | /11 |
| 255.240.0.0 | /12 |
| 255.248.0.0 | /13 |
| 255.252.0.0 | /14 |
| 255.254.0.0 | /15 |
| 255.255.0.0 | /16 |
| 255.255.128.0 | /17 |
| 255.255.192.0 | /18 |
| 255.255.224.0 | /19 |
| 255.255.240.0 | /20 |
| 255.255.248.0 | /21 |
| 255.255.252.0 | /22 |
| 255.255.254.0 | /23 |
| 255.255.255.0 | /24 |
| 255.255.255.128 | /25 |
| 255.255.255.192 | /26 |
| 255.255.255.224 | /27 |
| 255.255.255.240 | /28 |
| 255.255.255.248 | /29 |
| 255.255.255.252 | /30 |
How to Create Subnets
To create a subnet follow these steps:
- Determine the number of required network IDs:
- One for each subnet
- One for each wide area network connection
- Determine the number of required host IDs per subnet:
- One for each TCP/IP host
- One for each router interface
- Based on the above requirements, create the following:
- One subnet mask for your entire network
- A unique subnet ID for each physical segment
- A range of host IDs for each subnet
Rules for Grouping IP Addresses
- All IP addresses in the same group must not be separated from each other by a router.
- IP addresses separated from each other by a router must be in different groups.
Subnetting Class C Addresses
- In a Class C address, only 8 bits are available for defining the hosts.
- Remember that subnet bits start at the left and go to the right, without skipping bits.
- We can’t use a /31 or /32 because we have to have at least 2 host bits for assigning IP addresses to hosts.
| Binary | Decimal | CIDR |
| 00000000 | /24 | |
| 10000000 | 128 | /25 |
| 11000000 | 192 | /26 |
| 11100000 | 224 | /27 |
| 11110000 | 240 | /28 |
| 11111000 | 248 | /29 |
| 11111100 | 252 | /30 |
Subnetting Class C Example 1#
- 2n, where n = the number of bits borrowed
- 21 = 2 subnets
- For each subnet, examine the last octet of the subnet address in binary
- Subnet 1: 00000000 = 0
- Subnet 2: 10000000 = 128
- To calculate the number of hosts per network, you use the formula of 2n–2, where n = the number of bits left for hosts
- 27 – 2 = 126
Implementing a Class C /25 logical network
Subnetting Class C Example 2#
- Calculate the number of subnets with this formula:
- 22 = 4 subnets
- To calculate the number of hosts, begin by examining the last octet. Notice these subnets:
- Subnet 1: 0 = 00000000
- Subnet 2: 64 = 01000000
- Subnet 3: 128 = 10000000
- Subnet 4: 192 = 11000000
- Apply the host calculation formula:
- 26 – 2 = 62 hosts per subnet
Implementing a Class C /26 logical network
Subnetting Class C Example 3#
- To accommodate six networks, subnet 192.168.1.0 /24 into address blocks using this formula:
- 23 = 8
- To get at least six subnets, borrow 3 host bits. A subnet mask of 255.255.255.224 provides the 3 additional network bits.
- To calculate the number of hosts, begin by examining the last octet. Notice these subnets:
- 0 = 00000000
- 32 = 00100000
- 64 = 01000000
- 96 = 01100000
- 128 = 10000000
- 160 = 10100000
- 192 = 11000000
- 224 = 11100000
- Apply the host calculation formula:
- 25 – 2 = 30 hosts per subnet
Fast Way Subnetting
- How many subnets?
- 2x = number of subnets. x is the number of masked bits, or the 1s.
- For example, in 11000000, the number of 1s gives us 22 subnets. In this example, there are 4 subnets.
- How many hosts per subnet?
- 2y – 2 = number of hosts per subnet. y is the number of unmasked bits, or the 0s.
- For example, in 11000000 the number of 0s gives us 26 – 2 hosts or 62 hosts per subnet
- What are the valid subnets?
- 256 – subnet mask = block size
- example would be 256 – 192 = 64 or increment number
Fast Way Subnetting
Case Study
- What is the subnet mask for this networks?
2x = number of subnets
2x = 8
2x = 23
x = 3
y = 32 – 24 – 3 = 5
→ 255.255.255.224 or /27 - What are the valid subnets?
256 – 224 = 32 or increment number
→ 0, 32, 64, 96, 128, 160, 192, 224
First Net-ID: 192.168.10.0/27
Valid-Host: 192.168.1 – 30 /27
Broadcast-ID: 192.168.10.31/27
Subnetting Class B Addresses
We can use up to 14 bits for subnetting
Decimal CIDR 255.255.128.0 /17 255.255.192.0 /18 255.255.224.0 /19 255.255.240.0 /20 255.255.248.0 /21 255.255.252.0 /22 255.255.254.0 /23 255.255.255.0 /24 255.255.255.128 /25 255.255.255.192 /26 255.255.255.224 /27 255.255.255.240 /28 255.255.255.248 /29 255.255.255.252 /30
Subnetting Class B Example
- Example Network address: 172.16.0.0
- Example Subnet mask: 255.255.128.0 (/17)
- How many subnets?
- 21 = 2
- How many hosts per subnet?
- 215 – 2 = 32,766
- Valid subnets?
- 256 – 128 = 128. → 0, 128
- Remember that subnetting is performed in the third octet, so the subnet numbers are really 0.0 and 128.0
| Subnet | 172.16.0.0 | 172.16.128.0 |
| First host | 172.16.0.1 | 172.16.128.1 |
| Last host | 172.16.127.254 | 172.255.254 |
| Broadcast | 172.16.127.255 | 172.16.255.255 |
Subnetting Class A Addresses
We can use up to 22 bits for subnetting
Decimal CIDR CIDR 255.128.0.0 /9 255.192.0.0 /10 255.224.0.0 /11 255.240.0.0 /12 255.248.0.0 /13 255.252.0.0 /14 255.254.0.0 /15 255.255.128.0 /17 255.255.192.0 /18 255.255.224.0 /19 255.255.240.0 /20 255.255.248.0 /21 255.255.252.0 /22 255.255.254.0 /23 255.255.255.0 /24 255.255.255.128 /25 255.255.255.192 /26 255.255.255.224 /27 255.255.255.240 /28 255.255.255.248 /29 255.255.255.252 /30
Subnetting Class A Example
- Example Network address: 10.0.0.0
- Example Subnet mask: 255.255.0.0 (/16)
- How many subnets?
- 28 = 256
- How many hosts per subnet?
- 216 – 2 = 65,534
- Valid subnets?
- 256 – 255 = 1. 0, 1, 2, 3, 4, etc (all in the second octet)
| Subnet | 10.0.0.0 | 10.1.0.0 | …………………… |
| First host | 10.0.0.1 | 10.1.0.1 | …………………… |
| Last host | 10.0.255.254 | 10.1.255.254 | …………………… |
| Broadcast | 10.0.255.255 | 10.1.255.255 | …………………… |
The End of The Word
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