diff -r c737d0a0e9a0 src/applications/udp-client-server/udp-client-server-test.cc --- a/src/applications/udp-client-server/udp-client-server-test.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/applications/udp-client-server/udp-client-server-test.cc Wed Apr 07 10:22:52 2010 +0200 @@ -161,7 +161,7 @@ apps.Start (Seconds (1.0)); apps.Stop (Seconds (10.0)); - uint32_t MaxPacketSize = 1400; + uint32_t MaxPacketSize = 1400-28; // ip/udp header UdpTraceClientHelper client (i.GetAddress (1), port,""); client.SetAttribute ("MaxPacketSize", UintegerValue (MaxPacketSize)); apps = client.Install (n.Get (0)); diff -r c737d0a0e9a0 src/devices/bridge/bridge-net-device.cc --- a/src/devices/bridge/bridge-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/bridge/bridge-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -22,6 +22,7 @@ #include "ns3/log.h" #include "ns3/boolean.h" #include "ns3/simulator.h" +#include "ns3/uinteger.h" NS_LOG_COMPONENT_DEFINE ("BridgeNetDevice"); @@ -36,6 +37,11 @@ static TypeId tid = TypeId ("ns3::BridgeNetDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0xffff), + MakeUintegerAccessor (&BridgeNetDevice::SetMtu, + &BridgeNetDevice::GetMtu), + MakeUintegerChecker ()) .AddAttribute ("EnableLearning", "Enable the learning mode of the Learning Bridge", BooleanValue (true), @@ -53,8 +59,7 @@ BridgeNetDevice::BridgeNetDevice () : m_node (0), - m_ifIndex (0), - m_mtu (0xffff) + m_ifIndex (0) { NS_LOG_FUNCTION_NOARGS (); m_channel = CreateObject (); diff -r c737d0a0e9a0 src/devices/csma/csma-net-device.cc --- a/src/devices/csma/csma-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/csma/csma-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -50,11 +50,10 @@ Mac48AddressValue (Mac48Address ("ff:ff:ff:ff:ff:ff")), MakeMac48AddressAccessor (&CsmaNetDevice::m_address), MakeMac48AddressChecker ()) - .AddAttribute ("FrameSize", - "The maximum size of a packet sent over this device.", - UintegerValue (DEFAULT_FRAME_SIZE), - MakeUintegerAccessor (&CsmaNetDevice::SetFrameSize, - &CsmaNetDevice::GetFrameSize), + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0xffff), + MakeUintegerAccessor (&CsmaNetDevice::SetMtu, + &CsmaNetDevice::GetMtu), MakeUintegerChecker ()) .AddAttribute ("EncapsulationMode", "The link-layer encapsulation type to use.", @@ -173,8 +172,6 @@ // to change it here. // m_encapMode = DIX; - m_frameSize = DEFAULT_FRAME_SIZE; - m_mtu = MtuFromFrameSize (m_frameSize); } CsmaNetDevice::~CsmaNetDevice() @@ -192,76 +189,14 @@ NetDevice::DoDispose (); } - uint32_t -CsmaNetDevice::MtuFromFrameSize (uint32_t frameSize) -{ - NS_LOG_FUNCTION (frameSize); - - NS_ASSERT_MSG (frameSize <= std::numeric_limits::max (), - "CsmaNetDevice::MtuFromFrameSize(): Frame size should be derived from 16-bit quantity: " << frameSize); - - uint32_t newSize; - - switch (m_encapMode) - { - case DIX: - newSize = frameSize - ETHERNET_OVERHEAD; - break; - case LLC: - { - LlcSnapHeader llc; - - NS_ASSERT_MSG ((uint32_t)(frameSize - ETHERNET_OVERHEAD) >= llc.GetSerializedSize (), - "CsmaNetDevice::MtuFromFrameSize(): Given frame size too small to support LLC mode"); - newSize = frameSize - ETHERNET_OVERHEAD - llc.GetSerializedSize (); - } - break; - case ILLEGAL: - default: - NS_FATAL_ERROR ("CsmaNetDevice::MtuFromFrameSize(): Unknown packet encapsulation mode"); - return 0; - } - - return newSize; -} - - uint32_t -CsmaNetDevice::FrameSizeFromMtu (uint32_t mtu) -{ - NS_LOG_FUNCTION (mtu); - - uint32_t newSize; - - switch (m_encapMode) - { - case DIX: - newSize = mtu + ETHERNET_OVERHEAD; - break; - case LLC: - { - LlcSnapHeader llc; - newSize = mtu + ETHERNET_OVERHEAD + llc.GetSerializedSize (); - } - break; - case ILLEGAL: - default: - NS_FATAL_ERROR ("CsmaNetDevice::FrameSizeFromMtu(): Unknown packet encapsulation mode"); - return 0; - } - - return newSize; -} - void CsmaNetDevice::SetEncapsulationMode (enum EncapsulationMode mode) { NS_LOG_FUNCTION (mode); m_encapMode = mode; - m_mtu = MtuFromFrameSize (m_frameSize); NS_LOG_LOGIC ("m_encapMode = " << m_encapMode); - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); NS_LOG_LOGIC ("m_mtu = " << m_mtu); } @@ -272,24 +207,13 @@ return m_encapMode; } - bool +bool CsmaNetDevice::SetMtu (uint16_t mtu) { - NS_LOG_FUNCTION (mtu); - - uint32_t newFrameSize = FrameSizeFromMtu (mtu); - - if (newFrameSize > std::numeric_limits::max ()) - { - NS_LOG_WARN ("CsmaNetDevice::SetMtu(): Frame size overflow, MTU not set."); - return false; - } - - m_frameSize = newFrameSize; + NS_LOG_FUNCTION (this << mtu); m_mtu = mtu; NS_LOG_LOGIC ("m_encapMode = " << m_encapMode); - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); NS_LOG_LOGIC ("m_mtu = " << m_mtu); return true; @@ -302,24 +226,6 @@ return m_mtu; } - void -CsmaNetDevice::SetFrameSize (uint16_t frameSize) -{ - NS_LOG_FUNCTION (frameSize); - - m_frameSize = frameSize; - m_mtu = MtuFromFrameSize (frameSize); - - NS_LOG_LOGIC ("m_encapMode = " << m_encapMode); - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); - NS_LOG_LOGIC ("m_mtu = " << m_mtu); -} - - uint16_t -CsmaNetDevice::GetFrameSize (void) const -{ - return m_frameSize; -} void CsmaNetDevice::SetSendEnable (bool sendEnable) @@ -381,7 +287,6 @@ NS_LOG_LOGIC ("p->GetSize () = " << p->GetSize ()); NS_LOG_LOGIC ("m_encapMode = " << m_encapMode); NS_LOG_LOGIC ("m_mtu = " << m_mtu); - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); uint16_t lengthType = 0; switch (m_encapMode) @@ -435,7 +340,7 @@ // but with an LLC/SNAP header added to the payload as in IEEE 802.2 // lengthType = p->GetSize (); - NS_ASSERT_MSG (lengthType <= m_frameSize - 18, + NS_ASSERT_MSG (lengthType <= GetMtu (), "CsmaNetDevice::AddHeader(): 802.3 Length/Type field with LLC/SNAP: " "length interpretation must not exceed device frame size minus overhead"); } diff -r c737d0a0e9a0 src/devices/csma/csma-net-device.h --- a/src/devices/csma/csma-net-device.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/csma/csma-net-device.h Wed Apr 07 10:22:52 2010 +0200 @@ -185,108 +185,10 @@ void SetReceiveEnable (bool enable); /** - * Set The max frame size of packets sent over this device. - * - * Okay, that was easy to say, but the details are a bit thorny. We have a MAC-level MTU that is the payload that higher - * level protocols see. We have a PHY-level MTU which is the maximum number of bytes we can send over the link - * (cf. 1500 bytes for Ethernet). We also have a frame size which is some total number of bytes in a packet which could - * or could not include any framing and overhead. There can be a lot of inconsistency in definitions of these terms. For - * example, RFC 1042 asserts that the terms maximum transmission unit and maximum packet size are equivalent. RFC 791, - * however, defines MTU as the maximum sized IP datagram that can be sent. Packet size and frame size are sometimes - * used interchangeably. - * - * So, some careful definitions are in order to avoid confusion: - * - * In real Ethernet, a packet on the wire starts with a preamble of seven bytes of alternating ones and zeroes followed by - * a Start-of-Frame-Delimeter (10101011). This is followed by what is usually called the packet: a MAC destination and - * source, a type field, payload, a possible padding field and a CRC. To be strictly and pedantically correct the frame - * size is necessarily larger than the packet size on a real Ethernet. But, this isn't a real Ethernet, it's a simulation - * of a device similar to Ethernet, and we have no good reason to add framing bits. So, in the case of the CSMA device, - * the frame size is equal to the packet size. Since these two values are equal, there is no danger in assuming they are - * identical. We do not implement any padding out to a minimum frame size, so padding is a non-issue. We define packet - * size to be equal to frame size and this excludes the preamble and SFD bytes of a real Ethernet frame. We define a - * single (MAC-level) MTU that coresponds to the payload size of the packet, which is the IP-centric view of the term as - * seen in RFC 791. - * - * To make this concrete, consider DIX II (Digital Equipment, Intel, Xerox type II) framing, which is used in most TCP/IP - * stacks. NetWare and Wireshark call this framing Ethernet II, by the way. In this framing scheme, a real packet on the - * wire starts with the preamble and Start-of-Frame-Delimeter (10101011). We ignore these bits on this device since it they - * are not needed. In DIX II, the SFD is followed by the MAC (48) destination address (6 bytes), source address (6 bytes), - * the EtherType field (2 bytes), payload (0-1500 bytes) and a CRC (4 bytes) -- this corresponds to our entire frame. The - * payload of the packet/frame in DIX can be from 0 to 1500 bytes. It is the maxmimum value of this payload that we call - * the MTU. Typically, one sees the MTU set to 1500 bytes and the maximum frame size set to 1518 bytes in Ethernet-based - * networks. - * - * Different framing schemes can make for different MTU and frame size relationships. For example, we support LLC/SNAP - * encapsulation which adds eight bytes of header overhead to the usual DIX framing. In this case, if the maximum frame - * size is left at 1518 bytes, we need to export an MTU that reflects the loss of eight bytes for a total of 1492. - * - * Another complication is that IEEE 802.1Q adds four bytes to the maximum frame size for VLAN tagging. In order to - * provide an MTU of 1500 bytes, the frame size would need to increased to 1522 bytes to absorb the additional overhead. - * - * So, there are really three variables that are not entirely free at work here. There is the maximum frame size, the - * MTU and the framing scheme which we call the encapsulation mode. - * - * So, what do we do since there are be three values which must always be consistent in the driver? Which values to we - * allow to be changed and how do we ensure the other two are consistent? We want to actually allow a user to change - * these three variables in flexible ways, but we want the results (even at intermediate stages of her ultimate change) to - * be consistent. We certainly don't want to require that users must understand the various requirements of an enapsulation - * mode in order to set these variables. - * - * Consider the following situation: A user wants to set the maximum frame size to 1418 bytes instead of 1518. This - * user shouldn't have to concern herself that the current encapuslation mode is LLC/SNAP and this will consume eight bytes. - * She should not have to also figure out that the MTU needs to be set to 1392 bytes, and she should certainly not have to - * do this in some special order to keep intermediate steps consistent. - * - * Similarly, a user who is interested in setting the MTU to 1400 bytes should not be forced to understand that - * (based on encapsulation mode) the frame size may need to be set to eighteen + eight bytes more than what he wants - * in certain cases (802,3 + LLC/SNAP), twenty-two + zero bytes in others (802.1Q) and other inscrutable combinations - * - * Now, consider a user who is only interested in changing the encapsulation mode from LLC/SNAP to DIX. This - * is going to change the relationship between the MTU and the frame size. We've may have to come up with a new value - * for at least one of the these? Which one? There are too many free variables. - * - * We could play games trying to figure out what the user wants to do, but that is typically a bad plan and programmers - * have a long and distinguished history of guessing wrong. We'll avoid all of that and just define a flexible behavior - * that can be worked to get what you want. Here it is: - * - * - If the user is changing the encapsulation mode, the PHY MTU will remain fixed and the MAC MTU will change, if required, - * to make the three values consistent; - * - * - If the user is changing the MTU, she is interested in getting that part of the system set, so the frame size - * will be changed to make the three values consistent; - * - * - If the user is changing the frame size, he is interested in getting that part of the system set, so the MTU - * will be changed to make the three values consistent; - * - * - You cannot define the MTU and frame size separately -- they are always tied together by the emulation mode. This - * is not a restriction. Consider what this means. Perhaps you want to set the frame size to some large number and the - * MTU to some small number. The largest packet you can send is going to be limited by the MTU, so it is not possible to - * send a frame larger than the MTU plus overhead. The larger frame size is not useful. - * - * So, if a user calls SetFrameSize, we assume that the maximum frame size is the interesting thing for that user and - * we just adjust the MTU to a new "correct value" based on the current encapsulation mode. If a user calls SetMtu, we - * assume that the MTU is the interesting property for that user, and we adjust the frame size to a new "correct value" - * for the current encapsulation mode. If a user calls SetEncapsulationMode, then we take the MTU as the free variable - * and set its value to match the current frame size. - * - * \param frameSize The max frame size of packets sent over this device. - */ - void SetFrameSize (uint16_t frameSize); - - /** - * Get The max frame size of packets sent over this device. - * - * \returns The max frame size of packets sent over this device. - */ - uint16_t GetFrameSize (void) const; - - /** * Set the encapsulation mode of this device. * * \param mode The encapsulation mode of this device. * - * \see SetFrameSize */ void SetEncapsulationMode (CsmaNetDevice::EncapsulationMode mode); @@ -456,20 +358,6 @@ void Init (bool sendEnable, bool receiveEnable); /** - * Calculate the value for the MTU that would result from - * setting the frame size to the given value. - * \param frameSize size of frame - */ - uint32_t MtuFromFrameSize (uint32_t frameSize); - - /** - * Calculate the value for the frame size that would be required - * to be able to set the MTU to the given value. - * \param mtu MTU - */ - uint32_t FrameSizeFromMtu (uint32_t mtu); - - /** * Start Sending a Packet Down the Wire. * * The TransmitStart method is the method that is used internally in @@ -804,15 +692,7 @@ */ TracedCallback<> m_linkChangeCallbacks; - static const uint16_t DEFAULT_FRAME_SIZE = 1518; - static const uint16_t ETHERNET_OVERHEAD = 18; - - /** - * The frame size/packet size. This corresponds to the maximum - * number of bytes that can be transmitted as a packet without framing. - * This corresponds to the 1518 byte packet size often seen on Ethernet. - */ - uint32_t m_frameSize; + static const uint16_t DEFAULT_MTU = 1500; /** * The Maxmimum Transmission Unit. This corresponds to the maximum diff -r c737d0a0e9a0 src/devices/emu/emu-net-device.cc --- a/src/devices/emu/emu-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/emu/emu-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -63,6 +63,10 @@ static TypeId tid = TypeId ("ns3::EmuNetDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0), // arbitrary un-used value because no setter + MakeUintegerAccessor (&EmuNetDevice::GetMtu), + MakeUintegerChecker ()) .AddAttribute ("Address", "The ns-3 MAC address of this (virtual) device.", Mac48AddressValue (Mac48Address ("ff:ff:ff:ff:ff:ff")), diff -r c737d0a0e9a0 src/devices/mesh/mesh-point-device.cc --- a/src/devices/mesh/mesh-point-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/mesh/mesh-point-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -39,6 +39,11 @@ static TypeId tid = TypeId ("ns3::MeshPointDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0xffff), + MakeUintegerAccessor (&MeshPointDevice::SetMtu, + &MeshPointDevice::GetMtu), + MakeUintegerChecker ()) .AddAttribute ( "RoutingProtocol", "The mesh routing protocol used by this mesh point.", PointerValue (), @@ -50,7 +55,7 @@ } MeshPointDevice::MeshPointDevice () : - m_ifIndex (0), m_mtu (1500) + m_ifIndex (0) { NS_LOG_FUNCTION_NOARGS (); m_channel = CreateObject (); diff -r c737d0a0e9a0 src/devices/point-to-point/point-to-point-net-device.cc --- a/src/devices/point-to-point/point-to-point-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/point-to-point/point-to-point-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -41,17 +41,16 @@ static TypeId tid = TypeId ("ns3::PointToPointNetDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (DEFAULT_MTU), + MakeUintegerAccessor (&PointToPointNetDevice::SetMtu, + &PointToPointNetDevice::GetMtu), + MakeUintegerChecker ()) .AddAttribute ("Address", "The MAC address of this device.", Mac48AddressValue (Mac48Address ("ff:ff:ff:ff:ff:ff")), MakeMac48AddressAccessor (&PointToPointNetDevice::m_address), MakeMac48AddressChecker ()) - .AddAttribute ("FrameSize", - "The maximum size of a packet sent over this device.", - UintegerValue (DEFAULT_FRAME_SIZE), - MakeUintegerAccessor (&PointToPointNetDevice::SetFrameSize, - &PointToPointNetDevice::GetFrameSize), - MakeUintegerChecker ()) .AddAttribute ("DataRate", "The default data rate for point to point links", DataRateValue (DataRate ("32768b/s")), @@ -152,16 +151,6 @@ m_currentPkt (0) { NS_LOG_FUNCTION (this); - - // - // A quick sanity check to ensure consistent constants. - // - PppHeader ppp; - NS_ASSERT_MSG (PPP_OVERHEAD == ppp.GetSerializedSize (), - "PointToPointNetDevice::PointToPointNetDevice(): PPP_OVERHEAD inconsistent"); - - m_frameSize = DEFAULT_FRAME_SIZE; - m_mtu = MtuFromFrameSize (m_frameSize); } PointToPointNetDevice::~PointToPointNetDevice () @@ -594,65 +583,11 @@ return Address (); } - uint32_t -PointToPointNetDevice::MtuFromFrameSize (uint32_t frameSize) -{ - NS_LOG_FUNCTION (frameSize); - NS_ASSERT_MSG (frameSize <= std::numeric_limits::max (), - "PointToPointNetDevice::MtuFromFrameSize(): Frame size should be derived from 16-bit quantity: " << - frameSize); - PppHeader ppp; - NS_ASSERT_MSG ((uint32_t)frameSize >= ppp.GetSerializedSize (), - "PointToPointNetDevice::MtuFromFrameSize(): Given frame size too small to support PPP"); - return frameSize - ppp.GetSerializedSize (); -} - - uint32_t -PointToPointNetDevice::FrameSizeFromMtu (uint32_t mtu) -{ - NS_LOG_FUNCTION (mtu); - - PppHeader ppp; - return mtu + ppp.GetSerializedSize (); -} - - void -PointToPointNetDevice::SetFrameSize (uint16_t frameSize) -{ - NS_LOG_FUNCTION (frameSize); - - m_frameSize = frameSize; - m_mtu = MtuFromFrameSize (frameSize); - - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); - NS_LOG_LOGIC ("m_mtu = " << m_mtu); -} - - uint16_t -PointToPointNetDevice::GetFrameSize (void) const -{ - return m_frameSize; -} - bool PointToPointNetDevice::SetMtu (uint16_t mtu) { - NS_LOG_FUNCTION (mtu); - - uint32_t newFrameSize = FrameSizeFromMtu (mtu); - - if (newFrameSize > std::numeric_limits::max ()) - { - NS_LOG_WARN ("PointToPointNetDevice::SetMtu(): Frame size overflow, MTU not set."); - return false; - } - - m_frameSize = newFrameSize; + NS_LOG_FUNCTION (this << mtu); m_mtu = mtu; - - NS_LOG_LOGIC ("m_frameSize = " << m_frameSize); - NS_LOG_LOGIC ("m_mtu = " << m_mtu); - return true; } diff -r c737d0a0e9a0 src/devices/point-to-point/point-to-point-net-device.h --- a/src/devices/point-to-point/point-to-point-net-device.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/point-to-point/point-to-point-net-device.h Wed Apr 07 10:22:52 2010 +0200 @@ -138,109 +138,6 @@ */ void Receive (Ptr p); - /** - * \brief Set the max frame size of L2 frames sent over this device. - * - * We use the following terminology. MTU is the maximum sized payload - * of the point-to-point frame. For example, if the MTU is 1500 bytes, - * then any IP datagram sent to the device must be smaller for equal to - * the MTU. The MTU is an attribute of base class NetDevice. - * - * The maximum frame size is the maximum size of the L2 frame that can - * be sent on the channel. Typically this is a bit larger than the MTU - * to account for framing and header overhead. Note that the maximum - * frame size constrains the MTU unless the L2 performs segmentation - * and reassembly. - * - * In real serial channel (HDLC, for example), the wire idles (sends - * all ones) until the channel begins sending a packet. - * A frame on the wire starts with a flag character (01111110). This is - * followed by what is usually called the packet: * address, control, - * payload, and a Frame Check Sequence (FCS). This is followed by - * another flag character. If the flag characters are used, then bit - * stuffing must be used to prevent flag characters from appearing in - * the packet and confusing the receiver. But, this isn't a real link, - * it's a simulation of a device similar to a point-to-point device, and - * we have no good reason to add framing bits and therefore to do - * bit-stuffing. So, in the case of the point-to-point device, the frame - * size is equal to the packet size. Since these two values are defined - * to be equal, there is no danger in assuming they are identical. - * We define packet size to be equal to frame size and this excludes - * the flag characters. We define a single (MAC-level) MTU that - * corresponds to the payload size of the packet, which is the - * IP-centric view of the term as seen in RFC 791. - * - * To make this concrete, consider an example PPP framing on a - * synchronous link. In this framing scheme, a real serial frame on the - * wire starts with a flag character, address and control characters, - * then a 16-bit PPP protocol ID (0x21 = IP). Then we would see the - * actual payload we are supposed to send, presumably an IP datagram. - * At then we see the FCS and finally another flag character to end - * the frame. We ignore the flag bits on this device since it they are - * not needed. We aren't really using HDLC to send frames across the - * link, so we don't need the address and control bits either. In fact, - * to encapsulate using unframed PPP all we need to do is prepend the - * two-byte protocol ID. - * - * Typically the limiting factor in frame size is due to hardware - * limitations in the underlying HDLC controller receive FIFO buffer size. - * This number can vary widely. For example, the Motorola MC92460 has - * a 64 KByte maximum frame size; the Intel IXP4XX series has a 16 - * KByte size. Older USARTs have a maximum frame size around 2KBytes, - * and typical PPP links on the Internet have their MTU set to 1500 - * bytes since this is what will typically be used on Ethernet segments - * and will avoid path MTU issues. We choose to make the default MTU - * 1500 bytes which then fixes the maximum frame size - * as described below. - * - * So, there are really two related variables at work here. There - * is the maximum frame size that can be sent over the - * link and there is the MTU. - * - * So, what do we do since these values must always be consistent in the - * driver? We want to actually allow a user to change these variables, - * but we want the results (even at intermediate stages of her ultimate - * change) to be consistent. We certainly don't want to require that - * users must understand the details of PPP encapsulation in order to - * set these variables. We therefore link these variables as follows: - * - * - If the user is changing the MTU, he or she is interested in - * getting that part of the system set, so the frame size - * will be changed to make it consistent; - * - * - If the user is changing the frame size, he or she is interested - * in getting that part of the system set, so the MTU will be changed - * to make it consistent; - * - * - You cannot define the MTU and frame size separately -- they are - * always tied together by the overhead of the PPP encapsulation. - * This is not a restriction. Consider what this means. Perhaps you - * want to set the frame size to some large number and the MTU to - * some small number. The largest packet you can send is going to - * be limited by the MTU, so it is not possible to send a frame - * larger than the MTU plus overhead. Having the ability to set a - * larger frame size is not useful. - * - * So, if a user calls SetFrameSize, we assume that the maximum frame - * size is the interesting thing for that user and we just adjust - * the MTU to a new "correct value" based on the current encapsulation - * mode. If a user calls SetMtu, we assume that the MTU is the - * interesting property for that user, and we adjust the frame size to - * a new "correct value" for the current encapsulation mode. If a - * user calls SetEncapsulationMode, then we take the MTU as the free - * variable and set its value to match the current frame size. - * - * \param frameSize The max frame size of packets sent over this device. - */ - void SetFrameSize (uint16_t frameSize); - - /** - * Get the max frame size of packets sent over this device. - * - * \returns The max frame size of packets sent over this device. - */ - uint16_t GetFrameSize (void) const; - // The remaining methods are documented in ns3::NetDevice* virtual void SetIfIndex(const uint32_t index); @@ -287,19 +184,6 @@ virtual void DoDispose (void); private: - /** - * Calculate the value for the MTU that would result from - * setting the frame size to the given value. - * \param frameSize size of frame - */ - uint32_t MtuFromFrameSize (uint32_t frameSize); - - /** - * Calculate the value for the frame size that would be required - * to be able to set the MTU to the given value. - * \param mtu MTU - */ - uint32_t FrameSizeFromMtu (uint32_t mtu); /** * \returns the address of the remote device connected to this device @@ -544,15 +428,6 @@ TracedCallback<> m_linkChangeCallbacks; static const uint16_t DEFAULT_MTU = 1500; - static const uint16_t PPP_OVERHEAD = 2; - static const uint16_t DEFAULT_FRAME_SIZE = DEFAULT_MTU + PPP_OVERHEAD; - - /** - * The frame size/packet size. This corresponds to the maximum - * number of bytes that can be transmitted as a packet without framing. - * This corresponds to the 1518 byte packet size often seen on Ethernet. - */ - uint32_t m_frameSize; /** * The Maxmimum Transmission Unit. This corresponds to the maximum diff -r c737d0a0e9a0 src/devices/tap-bridge/tap-bridge.cc --- a/src/devices/tap-bridge/tap-bridge.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/tap-bridge/tap-bridge.cc Wed Apr 07 10:22:52 2010 +0200 @@ -33,6 +33,7 @@ #include "ns3/simulator.h" #include "ns3/realtime-simulator-impl.h" #include "ns3/system-thread.h" +#include "ns3/uinteger.h" #include #include @@ -74,6 +75,11 @@ static TypeId tid = TypeId ("ns3::TapBridge") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0), + MakeUintegerAccessor (&TapBridge::SetMtu, + &TapBridge::GetMtu), + MakeUintegerChecker ()) .AddAttribute ("DeviceName", "The name of the tap device to create.", StringValue (""), @@ -126,7 +132,6 @@ TapBridge::TapBridge () : m_node (0), m_ifIndex (0), - m_mtu (0), m_sock (-1), m_startEvent (), m_stopEvent (), diff -r c737d0a0e9a0 src/devices/virtual-net-device/virtual-net-device.cc --- a/src/devices/virtual-net-device/virtual-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/virtual-net-device/virtual-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -27,6 +27,7 @@ #include "virtual-net-device.h" #include "ns3/channel.h" #include "ns3/trace-source-accessor.h" +#include "ns3/uinteger.h" NS_LOG_COMPONENT_DEFINE ("VirtualNetDevice"); @@ -41,6 +42,11 @@ static TypeId tid = TypeId ("ns3::VirtualNetDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (0xffff), + MakeUintegerAccessor (&VirtualNetDevice::SetMtu, + &VirtualNetDevice::GetMtu), + MakeUintegerChecker ()) .AddTraceSource ("MacTx", "Trace source indicating a packet has arrived for transmission by this device", MakeTraceSourceAccessor (&VirtualNetDevice::m_macTxTrace)) @@ -69,7 +75,6 @@ { m_needsArp = false; m_supportsSendFrom = true; - m_mtu = 65535; m_isPointToPoint = true; } diff -r c737d0a0e9a0 src/devices/virtual-net-device/virtual-net-device.h --- a/src/devices/virtual-net-device/virtual-net-device.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/virtual-net-device/virtual-net-device.h Wed Apr 07 10:22:52 2010 +0200 @@ -91,8 +91,7 @@ void SetSupportsSendFrom (bool supportsSendFrom); /** - * \brief Configure the reported MTU for the virtual device. The - * default value is 65535. + * \brief Configure the reported MTU for the virtual device. * \param mtu MTU value to set * \return whether the MTU value was within legal bounds */ diff -r c737d0a0e9a0 src/devices/wifi/wifi-mac.cc --- a/src/devices/wifi/wifi-mac.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wifi/wifi-mac.cc Wed Apr 07 10:22:52 2010 +0200 @@ -175,11 +175,6 @@ TimeValue (GetDefaultMaxPropagationDelay ()), MakeTimeAccessor (&WifiMac::m_maxPropagationDelay), MakeTimeChecker ()) - .AddAttribute ("MaxMsduSize", "The maximum size of an MSDU accepted by the MAC layer." - "This value conforms to the specification.", - UintegerValue (2304), - MakeUintegerAccessor (&WifiMac::m_maxMsduSize), - MakeUintegerChecker (1,2304)) .AddAttribute ("Ssid", "The ssid we want to belong to.", SsidValue (Ssid ("default")), MakeSsidAccessor (&WifiMac::GetSsid, @@ -232,12 +227,6 @@ return m_maxPropagationDelay; } -uint32_t -WifiMac::GetMaxMsduSize (void) const -{ - return m_maxMsduSize; -} - void WifiMac::NotifyTx (Ptr packet) { diff -r c737d0a0e9a0 src/devices/wifi/wifi-mac.h --- a/src/devices/wifi/wifi-mac.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wifi/wifi-mac.h Wed Apr 07 10:22:52 2010 +0200 @@ -111,10 +111,6 @@ * Unused for now. */ Time GetMaxPropagationDelay (void) const; - /** - * \returns the maximum size of a MAC-level data payload. - */ - uint32_t GetMaxMsduSize (void) const; /** * \returns the MAC address associated to this MAC layer. @@ -246,7 +242,6 @@ virtual void FinishConfigureStandard (enum WifiPhyStandard standard) = 0; Time m_maxPropagationDelay; - uint32_t m_maxMsduSize; void Configure80211a (void); void Configure80211b (void); diff -r c737d0a0e9a0 src/devices/wifi/wifi-net-device.cc --- a/src/devices/wifi/wifi-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wifi/wifi-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -42,6 +42,11 @@ static TypeId tid = TypeId ("ns3::WifiNetDevice") .SetParent () .AddConstructor () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (MAX_MSDU_SIZE), + MakeUintegerAccessor (&WifiNetDevice::SetMtu, + &WifiNetDevice::GetMtu), + MakeUintegerChecker (1,MAX_MSDU_SIZE)) .AddAttribute ("Channel", "The channel attached to this device", PointerValue (), MakePointerAccessor (&WifiNetDevice::DoGetChannel), @@ -66,8 +71,7 @@ } WifiNetDevice::WifiNetDevice () - : m_mtu (0), - m_configComplete (false) + : m_configComplete (false) { NS_LOG_FUNCTION_NOARGS (); } @@ -187,9 +191,7 @@ bool WifiNetDevice::SetMtu (const uint16_t mtu) { - UintegerValue maxMsduSize; - m_mac->GetAttribute ("MaxMsduSize", maxMsduSize); - if (mtu > maxMsduSize.Get () || mtu == 0) + if (mtu > MAX_MSDU_SIZE) { return false; } @@ -199,12 +201,6 @@ uint16_t WifiNetDevice::GetMtu (void) const { - if (m_mtu == 0) - { - UintegerValue maxMsduSize; - m_mac->GetAttribute ("MaxMsduSize", maxMsduSize); - m_mtu = maxMsduSize.Get (); - } return m_mtu; } bool diff -r c737d0a0e9a0 src/devices/wifi/wifi-net-device.h --- a/src/devices/wifi/wifi-net-device.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wifi/wifi-net-device.h Wed Apr 07 10:22:52 2010 +0200 @@ -103,6 +103,10 @@ virtual bool SupportsSendFrom (void) const; private: + + // This value conforms to the 802.11 specification + static const uint16_t MAX_MSDU_SIZE = 2304; + virtual void DoDispose (void); virtual void DoStart (void); void ForwardUp (Ptr packet, Mac48Address from, Mac48Address to); diff -r c737d0a0e9a0 src/devices/wimax/wimax-net-device.cc --- a/src/devices/wimax/wimax-net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wimax/wimax-net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -57,6 +57,12 @@ .SetParent () + .AddAttribute ("Mtu", "The MAC-level Maximum Transmission Unit", + UintegerValue (MAX_MSDU_SIZE), + MakeUintegerAccessor (&WimaxNetDevice::SetMtu, + &WimaxNetDevice::GetMtu), + MakeUintegerChecker (0,MAX_MSDU_SIZE)) + .AddAttribute ("Phy", "The PHY layer attached to this device.", PointerValue (), @@ -81,12 +87,6 @@ MakeUintegerAccessor (&WimaxNetDevice::GetTtg, &WimaxNetDevice::SetTtg), MakeUintegerChecker (0, 120)) - .AddAttribute ("MaxMsduSize", - "The maximum size of an MSDU accepted by the MAC layer.", - UintegerValue (1500), - MakeUintegerAccessor (&WimaxNetDevice::m_maxMsduSize), - MakeUintegerChecker (1, 1500)) - .AddAttribute ("ConnectionManager", "The connection manager attached to this device.", PointerValue (), @@ -127,8 +127,7 @@ } WimaxNetDevice::WimaxNetDevice (void) - : m_mtu (0), - m_state (0), + : m_state (0), m_symbolIndex (0), m_ttg (0), m_rtg (0) @@ -164,11 +163,6 @@ NetDevice::DoDispose (); } -uint32_t -WimaxNetDevice::GetMaxMsduSize (void) const -{ - return m_maxMsduSize; -} void WimaxNetDevice::SetTtg (uint16_t ttg) @@ -233,7 +227,7 @@ bool WimaxNetDevice::SetMtu (const uint16_t mtu) { - if (mtu > m_maxMsduSize || mtu == 0) + if (mtu > MAX_MSDU_SIZE) { return false; } @@ -244,10 +238,6 @@ uint16_t WimaxNetDevice::GetMtu (void) const { - if (m_mtu == 0) - { - m_mtu = m_maxMsduSize; - } return m_mtu; } diff -r c737d0a0e9a0 src/devices/wimax/wimax-net-device.h --- a/src/devices/wimax/wimax-net-device.h Tue Apr 06 11:34:06 2010 +0400 +++ b/src/devices/wimax/wimax-net-device.h Wed Apr 07 10:22:52 2010 +0200 @@ -68,7 +68,6 @@ static TypeId GetTypeId (void); WimaxNetDevice (void); virtual ~WimaxNetDevice (void); - uint32_t GetMaxMsduSize (void) const; /** * \param ttg transmit/receive transition gap */ @@ -221,6 +220,8 @@ WimaxNetDevice (const WimaxNetDevice &); WimaxNetDevice & operator= (const WimaxNetDevice &); + static const uint16_t MAX_MSDU_SIZE = 1500; + virtual bool DoSend (Ptr packet, const Mac48Address& source, const Mac48Address& dest, @@ -239,7 +240,6 @@ std::string m_name; bool m_linkUp; Callback m_linkChange; - uint32_t m_maxMsduSize; mutable uint16_t m_mtu; // temp, shall be in BS. defined here to allow SS to access. SS shall actually determine it from DLFP, shall be moved to BS after DLFP is implemented diff -r c737d0a0e9a0 src/node/net-device.cc --- a/src/node/net-device.cc Tue Apr 06 11:34:06 2010 +0400 +++ b/src/node/net-device.cc Wed Apr 07 10:22:52 2010 +0200 @@ -33,13 +33,6 @@ { static TypeId tid = TypeId ("ns3::NetDevice") .SetParent